Lab_III_3_24_11_2020

Hello, world!
i like this subject but i do understand well 
['a', 'b', 'd', 'e']
dict_keys(['a', 'b', 'c', 'd', 'e', 'f'])
a ['c']
b ['c', 'e']
c ['a', 'b', 'd', 'e']
d ['c']
e ['c', 'b']
f []
Total numbers of appends:  10
[('a', 'c'), ('b', 'c'), ('b', 'e'), ('c', 'a'), ('c', 'b'), ('c', 'd'), ('c', 'e'), ('d', 'c'), ('e', 'c'), ('e', 'b')]
Total numbers of appends:  0
[]
Total numbers of appends:  12
[('a', 'b'), ('a', 'c'), ('a', 'd'), ('b', 'a'), ('b', 'c'), ('b', 'd'), ('c', 'a'), ('c', 'b'), ('c', 'd'), ('d', 'a'), ('d', 'b'), ('d', 'c')]
Total numbers of appends:  20
[('a', 'c'), ('a', 'b'), ('a', 'd'), ('a', 'e'), ('b', 'c'), ('b', 'a'), ('b', 'd'), ('b', 'e'), ('c', 'b'), ('c', 'a'), ('c', 'd'), ('c', 'e'), ('d', 'c'), ('d', 'a'), ('d', 'b'), ('d', 'e'), ('e', 'c'), ('e', 'a'), ('e', 'd'), ('e', 'b')]