diff --git a/youngjin.han/learning-node02-2020.org b/youngjin.han/learning-node02-2020.org
index 2d97fd6..0f5c6aa 100644
--- a/youngjin.han/learning-node02-2020.org
+++ b/youngjin.han/learning-node02-2020.org
@@ -1,3 +1,84 @@
+* 2020-06-17
+*** Python #11:
+**** DONE Lecture content
+     CLOSED: [2020-06-17 수 22:24]
+     - Same structure as "Python #2"
+     - Exercise 44
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-06-15
+*** DONE Python #10:
+    CLOSED: [2020-06-15 월 23:55]
+**** Lecture content
+     - Same structure as "Python #2"
+     - Exercise 43
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-06-12
+*** Python #9:
+**** DONE Lecture content
+     CLOSED: [2020-06-12 금 22:43]
+     - Same structure as "Python #2"
+     - Exercise 42
+     - Review all previous exercises, ensure you understand them
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-06-10
+*** Python #8:
+**** DONE Lecture content
+     CLOSED: [2020-06-11 목 00:00]
+     - Same structure as "Python #2"
+     - Exercises 40-41
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-06-08
+*** Python #7:
+**** DONE Lecture content
+     CLOSED: [2020-06-08 월 22:49]
+     - Same structure as "Python #2"
+     - Exercises 37-39
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-06-01
+*** Python applying learnings from 1..6
+**** DONE Lecture notes
+     CLOSED: [2020-06-02 화 11:21]
+     - Previous topics covered:
+       - Printing
+       - Formatting
+       - Variables
+       - Escape Sequences
+       - Inputting text
+       - Reading arguments / using argv
+       - Reading files
+       - Defining methods
+       - Boolean logic
+       - Branching using if/else/elif
+       - Loops: for/while
+     - Today we write a calculator that saves results in a file in python
+       - How it works in general
+         You read the input until you read a line that only contains a
+         "q". Every input line consists of numbers separated by a
+         space. For instance "4 5 9". You will need to .split() the
+         input.
+     - Steps
+       - Create a python script named "calc.py"
+       - It takes 1 command line argument (argv), which is the filename
+         - We will store the calculations *and* results in this file
+       - Create a method named "input_and_calculate_one_line"
+         - It does not have any arguments
+         - It reads one line via *input*
+         - It splits the input (let's say "4 5 9" => [ "4", "5", "9") ])
+         - It calculates the result (f.i. 4+5+9 = 18) and stores it in
+           a variable (use *sum* over the *list*)
+         - It returns a string of the format "4 + 5 + 9 = 18"
+         - If the line only contains a "q" it return "" (an empty string)
+       - Create a method named "editor" that takes a filename as an argument
+         - It opens the file for writing
+         - It uses input_and_calculate_one_line in a while loop
+         - while the return result is not "", we append the string to
+           the file
+         - When the return result is "", the function exits
 * 2020-05-29
 *** Python #6:
 **** DONE Lecture content
diff --git a/youngjin.han/python-the-hard-way/calc.py b/youngjin.han/python-the-hard-way/calc.py
new file mode 100644
index 0000000..5bfd45b
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/calc.py
@@ -0,0 +1,45 @@
+import sys
+
+a_py_file, a_calc_file = sys.argv
+
+def input_and_calculate_one_line():
+    l_input_array = list()
+    l_s_result = ""
+    l_input_string_num = 0
+    l_input_string = input("""Only numbers and spaces are allowed.
+'q' is exit.
+ > """).split()
+
+    if "q" != l_input_string[0] or 1 != len(l_input_string):
+        try:
+            for i in l_input_string:
+                l_input_string_num += 1
+                l_input_array.append(int(i))
+
+                if l_input_string_num != len(l_input_string):
+                    l_s_result += f"{i} + "
+                else:
+                    l_s_result += f"{i} = "
+
+            l_result = sum(l_input_array)
+            l_s_result += f"{l_result}"
+        except:
+            l_s_result = f"input error : input string = {l_input_string}"
+            print(l_s_result)
+
+    return l_s_result
+
+def editor(p_calc_file):
+    l_calc_result = open(p_calc_file, 'w')
+    l_calc_result.write("")
+    l_calc_result.close()
+    while True:
+        l_s_result = input_and_calculate_one_line()
+        if "" != l_s_result:
+            l_calc_result = open(p_calc_file, 'a')
+            l_calc_result.write(f"""{l_s_result}\n""")
+            l_calc_result.close()
+        else:
+            exit(0)
+
+editor(a_calc_file)
diff --git a/youngjin.han/python-the-hard-way/ex38.py b/youngjin.han/python-the-hard-way/ex38.py
new file mode 100644
index 0000000..db09084
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex38.py
@@ -0,0 +1,23 @@
+ten_things = "Apples Oranges Crows Telephone Light Sugar"
+
+print("Wait there are not 10 things in that list. Let's fix that.")
+
+stuff = ten_things.split(' ')
+more_stuff = ["Day", "Night", "Song", "Frisbee",
+              "Corn", "Banana", "Girl", "Boy"]
+
+while len(stuff) != 10:
+    next_one = more_stuff.pop()
+    print("Adding: ", next_one)
+    stuff.append(next_one)
+    print(f"There are {len(stuff)} items now.")
+
+print("There we go: ", stuff)
+
+print("Let's do some things with stuff.")
+
+print(stuff[1])
+print(stuff[-1]) # whoa! fancy
+print(stuff.pop())
+print(' '.join(stuff)) # what? cool!
+print('#'.join(stuff[3:5])) # super stellar!
diff --git a/youngjin.han/python-the-hard-way/ex39.py b/youngjin.han/python-the-hard-way/ex39.py
new file mode 100644
index 0000000..f9bc7ed
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex39.py
@@ -0,0 +1,65 @@
+# create a mapping of state to abbreviation
+states = {
+    'Oregon': 'OR',
+    'Florida': 'FL',
+    'California': 'CA',
+    'New York': 'NY',
+    'Michigan': 'MI',
+    'Texas': 'TX'
+}
+
+# create a basic set of states and some cities in them
+cities = {
+    'CA': 'San Francisco',
+    'MI': 'Detroit',
+    'FL': 'Jacksonville',
+    'Gyeonggi-do': 'Sungnam',
+    'Chungcheongbuk-do': 'Cheongju'
+}
+
+# add some more cities
+cities['NY'] = 'New York'
+cities['OR'] = 'Portland'
+cities['TX'] = 'Houston'
+
+# print out some cities
+print('-' * 10)
+print("NY State has: ", cities['NY'])
+print("OR State has: ", cities['OR'])
+
+# print some states
+print('-' * 10)
+print("Michigan's abbreviation is: ", states['Michigan'])
+print("Florida's abbreviation is: ", states['Florida'])
+
+# do it by using the state then cities dict
+print('-' * 10)
+print("Michigan has: ", cities[states['Michigan']])
+print("Florida has: ", cities[states['Florida']])
+
+# print every state abbreviation
+print('-' * 10)
+for state, abbrev in list(states.items()):
+    print(f"{state} is abbreviated {abbrev}")
+
+# print every city in state
+print('-' * 10)
+for abbrev, city in list(cities.items()):
+    print(f"{abbrev} has the city {city}")
+
+# now do both at the same time
+print('-' * 10)
+for state, abbrev in list(states.items()):
+    print(f"{state} state is abbreviated {abbrev}")
+    print(f"and has city {cities[abbrev]}")
+
+print('-' * 10)
+# safely get a abbreviation by state that might not be there
+state = states.get('Texas')
+
+if not state:
+    print("Sorry, no Texas.")
+
+# get a city with a default value
+city = cities.get('TX', 'Does Not Exist')
+print(f"The city for the state 'TX' is: {city}")
diff --git a/youngjin.han/python-the-hard-way/ex40a.py b/youngjin.han/python-the-hard-way/ex40a.py
new file mode 100644
index 0000000..73b5ddc
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex40a.py
@@ -0,0 +1,58 @@
+#mystuff = {'apple': "I AM APPLES!"}
+#print(mystuff['apple'])
+#
+#import mystuff
+#mystuff.apple()
+#
+#import mystuff
+#
+#mystuff.apple()
+#print(mystuff.tangerine)
+#
+#mystuff['apple'] # get apple from dict
+#mystuff.apple() # get apple from the module
+#mystuff.tangerine # same thing, it's just a variable
+#
+#class MyStuff(object):
+#
+#    def __init__(self):
+#        self.tangerine = "And now a thousand years between"
+#
+#    def apple(self):
+#        print("I AM CLASSY APPLES!")
+#
+#thing = MyStuff()
+#thing.apple()
+#print(thing.tangerine)
+#
+## dict style
+#mystuff['apples']
+#
+## module style
+#mystuff.apples()
+#print(mystuff.tangerine)
+#
+## class style
+#thing = MyStuff()
+#thing.apples()
+#print(thing.tangerine)
+#
+class Song(object):
+
+    def __init__(self, lyrics):
+        self.lyrics = lyrics
+
+    def sing_me_a_song(self):
+        for line in self.lyrics:
+            print(line)
+
+happy_bday = Song(["Happy birthday to you",
+                   "I don't want to get sued",
+                   "So I'll stop right there"])
+
+bulls_on_parade = Song(["They rally around tha family",
+                        "With pockets full of shells"])
+
+happy_bday.sing_me_a_song()
+
+bulls_on_parade.sing_me_a_song()
diff --git a/youngjin.han/python-the-hard-way/ex41.py b/youngjin.han/python-the-hard-way/ex41.py
new file mode 100644
index 0000000..3a8429c
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex41.py
@@ -0,0 +1,84 @@
+import random
+from urllib.request import urlopen
+import sys
+
+WORD_URL = "http://learncodethehardway.org/words.txt"
+WORDS = []
+
+PHRASES = {
+    "class %%%(%%%):":
+    "Make a class named %%% that is-a %%%.",
+    "class %%%(object):\n\tdef __init__(self, ***)" :
+    "class %%% has-a __init__ that takes self and *** params.",
+    "class %%%(object):\n\tdef ***(self, @@@)":
+    "class %%% has-a function *** that takes self and @@@ params.",
+    "*** = %%%()":
+    "Set *** to an instance of class %%%.",
+    "***.***(@@@)":
+    "From *** get the *** function, call it with params self, @@@.",
+    "***.*** = '***'":
+    "From *** get the *** attribute and set it to '***'."
+}
+
+# do they want to drill phrases first
+if len(sys.argv) == 2 and sys.argv[1] == "english":
+    PHRASE_FIRST = True
+else:
+    PHRASE_FIRST = False
+
+# load up the words from the website
+for word in urlopen(WORD_URL).readlines():
+    WORDS.append(str(word.strip(), encoding="utf-8"))
+
+
+def convert(snippet, phrase):
+    class_names = [w.capitalize() for w in
+                   random.sample(WORDS, snippet.count("%%%"))]
+    other_names = random.sample(WORDS, snippet.count("***"))
+    results = []
+    param_names = []
+
+    for i in range(0, snippet.count("@@@")):
+        param_count = random.randint(1,3)
+        param_names.append(', '.join(
+            random.sample(WORDS, param_count)))
+
+    for sentence in snippet, phrase:
+        # this is how you duplicate a list or string
+        result = sentence[:]
+
+        # fake class names
+        for word in class_names:
+            result = result.replace("%%%", word, 1)
+
+        # fake other names
+        for word in other_names:
+            result = result.replace("***", word, 1)
+
+        # fake parameter lists
+        for word in param_names:
+            result = result.replace("@@@", word, 1)
+
+        results.append(result)
+
+    return results
+
+
+# keep going until they hit CTRL-D
+try:
+    while True:
+        snippets = list(PHRASES.keys())
+        random.shuffle(snippets)
+
+        for snippet in snippets:
+            phrase = PHRASES[snippet]
+            question, answer = convert(snippet, phrase)
+            if PHRASE_FIRST:
+                question, answer = answer, question
+
+            print(question)
+
+            input("> ")
+            print(f"ANSWER: {answer}\n\n")
+except EOFError:
+    print("\nBye")
diff --git a/youngjin.han/python-the-hard-way/ex42.py b/youngjin.han/python-the-hard-way/ex42.py
new file mode 100644
index 0000000..f6341cc
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex42.py
@@ -0,0 +1,94 @@
+## Animal is parents
+## Animal is-a object (yes, sort of confusing) look at the extra credit
+class Animal(object):
+    pass
+
+## Animal is parents and Dog is child
+## Dog is-a Animal and has-a __init__ that takes self and name parameters
+class Dog(Animal):
+
+    def __init__(self, name):
+        ## Dos has-a name
+        self.name = name
+
+## Animal is parents and Cat is child
+## Cat is-a Animal and has-a __init__ that takes self and name parameters
+class Cat(Animal):
+
+    def __init__(self, name):
+        ## Cat has-a name
+        self.name = name
+
+## Person is parents
+## Person is-a object and has-a __init__ that takes self and name parameters
+class Person(object):
+
+    def __init__(self, name):
+        ## Person has-a name
+        self.name = name
+
+        ## Person has-a pet of some kind
+        self.pet = None
+
+## Persion is parents and Employee is child
+## Employee is-a Person and has-a __init__ that takes self and name parameters
+class Employee(Person):
+
+    def __init__(self, name, salary):
+        ## ?? hmm what is this strange magic?
+        ## From super, get the __init__ function, and call it with parameters self, name
+        super(Employee, self).__init__(name)
+        ## Employee has-a salary
+        self.salary = salary
+
+## Fish is parents
+## Fish is-a object
+class Fish(object):
+    pass
+
+## Fish is parents and Salmon is child
+## Salmon is-a Fish
+class Salmon(Fish):
+    pass
+
+## Fish is parents and Halibut is child
+## Halibut is-a Fish
+class Halibut(Fish):
+    pass
+
+
+## Set rover to an instance of class Dog
+## rover is-a Dog that has-a name is-a Rover
+rover = Dog("Rover")
+
+## Set satan to an instance of class Cat
+## stan is-a cat that has-a name is-a Satan
+satan = Cat("Satan")
+
+## Set mary to an instance of class Person
+## mary is-a Person that has-a name is-a Mary
+mary = Person("Mary")
+
+## From mary, get the pet attribute, and set it to satan
+## mary's pet is-a cat that has-a name that is-a Satan
+mary.pet = satan
+
+## Set frank to an instance of class Employee
+## frank is-a Employee and salary is-a 120000
+frank = Employee("Frank", 120000)
+
+## From frank, get the pet attribute, and set it to rover
+## frank's pet is-a dog that has-a name that is-a Rover
+frank.pet = rover
+
+## Set flipper to an instance of class Fish
+## flipper is-a Fish
+flipper = Fish()
+
+## Set crouse to an instance of class Salmon
+## crouse is-a Salmon
+crouse = Salmon()
+
+## Set harry to an instance of class Halibut
+## harry is-a Halibut
+harry = Halibut()
diff --git a/youngjin.han/python-the-hard-way/ex43.py b/youngjin.han/python-the-hard-way/ex43.py
new file mode 100644
index 0000000..798a9f3
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex43.py
@@ -0,0 +1,266 @@
+from sys import exit
+from random import randint
+from textwrap import dedent
+
+class Scene(object):
+
+    def enter(self):
+        print("This scene is not yet configured.")
+        print("Subclass it and implement enter().")
+        exit(1)
+
+class Engine(object):
+
+    def __init__(self, scene_map):
+        self.scene_map = scene_map
+
+    def play(self):
+        current_scene = self.scene_map.opening_scene()
+        last_scene = self.scene_map.next_scene('finished')
+
+        while current_scene != last_scene:
+            next_scene_name = current_scene.enter()
+            current_scene = self.scene_map.next_scene(next_scene_name)
+
+        # be sure to print out the last scene
+        current_scene.enter()
+        
+class Death(Scene):
+
+    quips = [
+        "You died. You kinda suck at this.",
+        "Your Mom would be proud...if she were smarter.",
+        "Such a luser.",
+        "I have a small puppy that's better at this.",
+        "You're worse than your Dad's jokes."
+
+        ]
+    
+    def enter(self):
+        print(Death.quips[randint(0, len(self.quips)-1)])
+        exit(1)
+
+class CentralCorridor(Scene):
+
+    def enter(self):
+        print(dedent("""
+            The Gothons of Planet Percal #25 have invaded your ship and
+            destroyed your entire crew. You are the last surviving
+            member and your last mission is to get the neutron destruct
+            bomb from the Weapons Armory, put it in the bridge, and
+            blow the ship up after getting into an escape pod.
+
+            You're running down the central corridor to the Weapons
+            Armory when a Gothon jumps out, red scaly skin, dark grimy
+            teeth, and evil clown costume flowing around his hate
+            filled body. He's blocking the door to the Armory and
+            about to pull a weapon to blast you.
+            """))
+
+        action = input("> ")
+
+        if action == "shoot!":
+            print(dedent("""
+                Quick on the draw you yank out your blaster and fire
+                it at the Gothon. His clown costume is flowing and
+                moving around his body, which throws off your aim.
+                Your laser hits his costume but misses him entirely.
+                This completely ruins his brand new costume his mother
+                bought him, which makes him fly into an insane rage
+                and blast you repeatedly in the face until you are
+                dead. Then he eats you.
+                """))
+            return 'death'
+
+        elif action == "dodge!":
+            print(dedent("""
+                Like a world class boxer you dodge, weave, slip and
+                slide right as the Gothon's blaster cranks a laser
+                past your head. In the middle of your artful dodge
+                your foot slips and you bang your head on the metal
+                wall and pass out. You wake up shortly after only to
+                die as the Gothon stomps on your head and eats you.
+                """))
+            return 'death'
+
+        elif action == "tell a joke" or int(action) == 0:
+            print(dedent("""
+                Lucky for you they made you learn Gothon insults in
+                the academy. You tell the one Gothon joke you know:
+                Lbhe zbgure vf fb sng, jura fur fvgf nebhaq gur ubhfr,
+                fur fvgf nebhaq gur ubhfr. The Gothon stops, tries
+                not to laugh, then busts out laughing and can't move.
+                While he's laughing you run up and shoot him square in
+                the head putting him down, then jump through the
+                Weapon Armory door.
+                """))
+            return 'laser_weapon_armory'
+
+        else:
+            print("DOES NOT COMPUTE!")
+            return 'central_corridor'
+    
+class LaserWeaponArmory(Scene):
+
+    def enter(self):
+        print(dedent("""
+            You do a dive roll into the Weapon Armory, crouch and scan
+            the room for more Gothons that might be hiding. It's dead
+            quiet, too quiet. You stand up and run to the far side of
+            the room and find the neutron bomb in its container.
+            There's a keypad lock on the box and you need the code to
+            get the bomb out. If you get the code wrong 10 times then
+            the lock closes forever and you can't get the bomb. The
+            code is 3 digits.
+            """))
+
+        code = f"{randint(1,9)}{randint(1,9)}{randint(1,9)}"
+        guess = input("[keypad]> ")
+        guesses = 0
+
+        while guess != code and guesses < 9:
+            print("BZZZZEDDD!")
+            guesses += 1
+            guess = input("[keypad]> ")
+
+        if guess == code or int(guess) == 0:
+            print(dedent("""
+                The container clicks open and the seal breaks, letting
+                gas out. You grab the neutron bomb and run as fast as
+                you can to the bridge where you must place it in the
+                right spot.
+                """))
+            return 'the_bridge'
+        else:
+            print(dedent("""
+                The lock buzzes one last time and then you hear a
+                sickening melting sound as the mechanism is fused
+                together. You decide to sit there, and finally the
+                Gothons blow up the ship from their ship and you die.
+                """))
+            return 'death'
+
+
+
+class TheBridge(Scene):
+
+    def enter(self):
+        print(dedent("""
+            You burst onto the Bridge with the netron destruct bomb
+            under your arm and surprise 5 Gothons who are trying to
+            take control of the ship. Each of them has an even uglier
+            clown costume than the last. They haven't pulled their
+            weapons out yet, as they see the active bomb under your
+            arm and don't want to set it off.
+            """))
+
+        action = input("> ")
+
+        if action == "throw the bomb":
+            print(dedent("""
+                In a panic you throw the bomb at the group of Gothons
+                and make a leap for the door. Right as you drop it a
+                Gothon shoots you right in the back killing you. As
+                you die you see another Gothon frantically try to
+                disarm the bomb. You die knowing they will probably
+                blow up when it goes off.
+                """))
+            return 'death'
+
+        elif action == "slowly place the bomb" or int(action) == 0:
+            print(dedent("""
+                You point your blaster at the bomb under your arm and
+                the Gothons put their hands up and start to sweat.
+                You inch backward to the door, open it, and then
+                carefully place the bomb on the floor, pointing your
+                blaster at it. You then jump back through the door,
+                punch the close button and blast the lock so the
+                Gothons can't get out. Now that the bomb is placed
+                you run to the escape pod to get off this tin can.
+                """))
+
+            return 'escape_pod'
+        else:
+            print("DOES NOT COMPUTE!")
+            return "the_bridge"
+
+
+class EscapePod(Scene):
+
+    def enter(self):
+        print(dedent("""
+            You rush through the ship desperately trying to make it to
+            the escape pod before the whole ship explodes. It seems
+            like hardly any Gothons are on the ship, so your run is
+            clear of interference. You get to the chamber with the
+            escape pods, and now need to pick one to take. Some of
+            them could be damaged but you don't have time to look.
+            There's 5 pods, which one do you take?
+            """))
+
+        good_pod = randint(1,5)
+        guess = input("[pod #]> ")
+
+
+        if int(guess) != good_pod:
+            print(dedent(f"""
+                You jump into pod {guess} and hit the eject button.
+                The pod escapes out into the void of space, then
+                implodes as the hull ruptures, crushing your body into
+                jam jelly.
+                """))
+            return 'death'
+        elif int(guess) == 0:
+            print(dedent(f"""
+                You jump into pod {guess} and hit the eject button.
+                The pod easily slides out into space heading to the
+                planet below. As it flies to the planet, you look
+                back and see your ship implode then explode like a
+                bright star, taking out the Gothon ship at the same
+                time. You won!
+                """))
+
+            return 'finished'
+            
+        else:
+            print(dedent(f"""
+                You jump into pod {guess} and hit the eject button.
+                The pod easily slides out into space heading to the
+                planet below. As it flies to the planet, you look
+                back and see your ship implode then explode like a
+                bright star, taking out the Gothon ship at the same
+                time. You won!
+                """))
+
+            return 'finished'
+
+class Finished(Scene):
+
+    def enter(self):
+        print("You won! Good job.")
+        return 'finished'
+
+class Map(object):
+
+    scenes = {
+        'central_corridor': CentralCorridor(),
+        'laser_weapon_armory': LaserWeaponArmory(),
+        'the_bridge': TheBridge(),
+        'escape_pod': EscapePod(),
+        'death': Death(),
+        'finished': Finished(),
+    }
+
+    def __init__(self, start_scene):
+        self.start_scene = start_scene
+
+    def next_scene(self, scene_name):
+        val = Map.scenes.get(scene_name)
+        return val
+
+    def opening_scene(self):
+        return self.next_scene(self.start_scene)
+
+a_map = Map('central_corridor')
+a_game = Engine(a_map)
+a_game.play()
diff --git a/youngjin.han/python-the-hard-way/ex44a.py b/youngjin.han/python-the-hard-way/ex44a.py
new file mode 100644
index 0000000..f43251b
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex44a.py
@@ -0,0 +1,13 @@
+class Parent(object):
+
+    def implicit(self):
+        print("PARENT implicit()")
+
+class Child(Parent):
+    pass
+
+dad = Parent()
+son = Child()
+
+dad.implicit()
+son.implicit()
diff --git a/youngjin.han/python-the-hard-way/ex44b.py b/youngjin.han/python-the-hard-way/ex44b.py
new file mode 100644
index 0000000..331295f
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex44b.py
@@ -0,0 +1,15 @@
+class Parent(object):
+
+    def override(self):
+        print("PARENT override()")
+
+class Child(Parent):
+
+    def override(self):
+        print("CHILD override()")
+
+dad = Parent()
+son = Child()
+
+dad.override()
+son.override()
diff --git a/youngjin.han/python-the-hard-way/ex44c.py b/youngjin.han/python-the-hard-way/ex44c.py
new file mode 100644
index 0000000..e935d04
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex44c.py
@@ -0,0 +1,17 @@
+class Parent(object):
+
+    def altered(self):
+        print("PARENT altered()")
+
+class Child(Parent):
+
+    def altered(self):
+        print("CHILD, BEFORE PARENT altered()")
+        super(Child, self).altered()
+        print("CHILD, AFTER PARENT altered()")
+
+dad = Parent()
+son = Child()
+
+dad.altered()
+son.altered()
diff --git a/youngjin.han/python-the-hard-way/ex44d.py b/youngjin.han/python-the-hard-way/ex44d.py
new file mode 100644
index 0000000..032df1e
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex44d.py
@@ -0,0 +1,32 @@
+class Parent(object):
+
+    def override(self):
+        print("PARENT override()")
+
+    def implicit(self):
+        print("PARENT implicit()")
+
+    def altered(self):
+        print("PARENT altered()")
+
+class Child(Parent):
+
+    def override(self):
+        print("CHILD override()")
+
+    def altered(self):
+        print("CHILD, BEFORE PARENT altered()")
+        super(Child, self).altered()
+        print("CHILD, AFTER PARENT altered()")
+
+dad = Parent()
+son = Child()
+
+dad.implicit()
+son.implicit()
+
+dad.override()
+son.override()
+
+dad.altered()
+son.altered()
diff --git a/youngjin.han/python-the-hard-way/ex44e.py b/youngjin.han/python-the-hard-way/ex44e.py
new file mode 100644
index 0000000..084abe1
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex44e.py
@@ -0,0 +1,32 @@
+class Other(object):
+
+    def override(self):
+        print("OTHER override()")
+
+    def implicit(self):
+        print("OTHER implicit()")
+
+    def altered(self):
+        print("OTHER altered()")
+
+class Child(object):
+
+    def __init__(self):
+        self.other = Other()
+
+    def implicit(self):
+        self.other.implicit()
+
+    def override(self):
+        print("CHILD override()")
+
+    def altered(self):
+        print("CHILD, BEFORE OTHER altered()")
+        self.other.altered()
+        print("CHILD, AFTER OTHER altered()")
+
+son = Child()
+
+son.implicit()
+son.override()
+son.altered()
diff --git a/youngjin.han/python-the-hard-way/mystuff.py b/youngjin.han/python-the-hard-way/mystuff.py
new file mode 100644
index 0000000..ce31c7d
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/mystuff.py
@@ -0,0 +1,5 @@
+def apple():
+    print("I AM APPLES!")
+
+# this is just a variable
+tangerine = "Living reflection of a dream"
diff --git a/youngjin.han/python-the-hard-way/result.txt b/youngjin.han/python-the-hard-way/result.txt
new file mode 100644
index 0000000..b50bbfe
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/result.txt
@@ -0,0 +1 @@
+input error : input string = ['1', 'q']
diff --git a/youngjin.han/python.org b/youngjin.han/python.org
index 7a8d03f..9b082d6 100644
--- a/youngjin.han/python.org
+++ b/youngjin.han/python.org
@@ -1,4 +1,33 @@
+* 2020-06-17
+** note
+  - ex44.py
+    - none
+* 2020-06-15
+** note
+  - ex43.py
+    - none
+* 2020-06-12
+** note
+  - ex42.py
+    - MRO(method resolution order)
+* 2020-06-10
+** note
+  - ex40.py
+    - none
+  - ex41.py
+    - none
+* 2020-06-08
+** note
+  - ex37.py
+    - none
+  - ex38.py
+    - ten_things.split(' ') == split(ten_things, ' ')
+    - more_stuff.pop() == pop(more_stuff)
+    - stuff.append(next_one) == append(stuff, next_one)
+  - ex39.py
+    - dictionaries do not use index number to search a key or a value.
 * 2020-05-29
+** note
   - ex32.py
     - remove, insert, index, append, '+' and del
   - ex33.py