pimento[w05]$ python3
Python 3.6.5 (default, Apr  1 2018, 05:46:30)
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> test_lst = [3,4]
>>> test_lst = test_lst.append(5)
>>> test_lst
>>> type(test_lst)
<class 'NoneType'>
>>> test_lst = test_lst.append(6)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'append'
>>>
>>>
>>> x = 7
>>> y = 4
>>>
>>> x = y
>>> y = x
>>>
>>> x
4
>>> y
4
>>>
>>> x = 7
>>> y = 4
>>>
>>> temp = x
>>>
>>> print(x,y,temp)
7 4 7
>>> x = y
>>> print(x,y,temp)
4 4 7
>>> y = temp
>>> print(x,y,temp)
4 7 7
>>> exit()
pimento[w05]$ atom shuffle_list.py
pimento[w05]$