import copy

b = copy.copy(a)

>>> a=[1,['a']]

>>> b=a

>>> c=copy.copy(a)

>>> a

[1, ['a']]

>>> b

[1, ['a']]

>>> c

[1, ['a']]

>>> id(a)

140556196249680

>>> id(b)

140556196249680

>>> id(c)

140556298139120

>>> a[0]=2

>>> a

[2, ['a']]

>>> c

[1, ['a']]

>>>a[1].append('b')

>>>a

[2,['a','b']]

>>>c

[1,['a','b']]

import copy

b = copy.deepcopy(a)

>>> a=[1,2,['a','b']]

>>> b=copy.deepcopy(a)

>>> a

[1, 2, ['a', 'b']]

>>> b

[1, 2, ['a', 'b']]

>>> id(a)

140556196175952

>>> id(b)

140556196501336

>>> id(a[0])

11961144

>>> id(b[0])

11961144

>>> id(a[2])

140556196424448

>>> id(b[2])

140556196250472

>>> a[0]=3

>>> a[2].append('c')

>>> a

[3, 2, ['a', 'b', 'c']]

>>> b

[1, 2, ['a', 'b']]