pimento[~]$ 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.
>>> greeting = "hello"
>>> greeting[0] = "m"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment
>>> greetingList = list(greeting)
>>> greeting
'hello'
>>> greetingList
['h', 'e', 'l', 'l', 'o']
>>> greetingList[0] = "m"
>>> greetingList
['m', 'e', 'l', 'l', 'o']
>>>