examples/lists/not_copy.py
from __future__ import print_function

x = ['apple', 'bob', 'cat', 'drone']
y = x
x[0] = 'qqrq'
print(x)    # ['qqrq', 'bob', 'cat', 'drone']
print(y)    # ['qqrq', 'bob', 'cat', 'drone']
examples/lists/real_copy.py
from __future__ import print_function

x = ['apple', 'bob', 'cat', 'drone']
y = x[:]

x[0] = 'qqrq'

print(x)    # ['qqrq', 'bob', 'cat', 'drone']
print(y)    # ['apple', 'bob', 'cat', 'drone']