Python 3.5.1 (v3.5.1:37a07cee5969, Dec  5 2015, 21:12:44) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
python_ta imported successfully!
help(list.copy)
Help on method_descriptor:
copy(...)
    L.copy() -> list -- a shallow copy of L
'x' * 4
'xxxx'
[0] * 3
[0, 0, 0]
[[0]] * 3
[[0], [0], [0]]
x = [[0]] * 3
x[0].append(4)
x
[[0, 4], [0, 4], [0, 4]]