Begin to introduce commented out code, use metadata

bin/checksum_from_scapy.py

@@ -23,6 +23,8 @@ else:
         # create array with unsigned shorts,
         # sum it up -> results in 16 bit uint (?)
         s = sum(array.array("H", pkt))
+        print("sum={}".format(s))
+        # This step is understood
 
         # (s & 0xffff) -> mask for 16 bit, truncate rest
         # (s >> 16) right shift by 16 bits
@@ -40,7 +42,6 @@ else:
         # over bits from the previous calculation
         s += s >> 16
 
-
         # according to https://stackoverflow.com/questions/8305199/the-tilde-operator-in-python
         # ~ is the bitwise complement operator in python
         # which essentially calculates -x - 1
@@ -65,3 +66,6 @@ if __name__ == '__main__':
     pkt_bytes = pkt.encode('utf-8')
     print(pkt_bytes)
     print(checksum(pkt_bytes))
+
+    ipv4 = "AAAA"
+    ipv6 = "BBAA"