You can use the # symbol to create a multiline comment in python code example

Example 1: python big comment

# one hashtag for a single line comment

"""
3 quote marks is technically
a docstring, but it works as
a multi line comment
"""

##pressing 'Alt 3' in IDLE comments out
##what you are selecting
and 'Alt 4' to uncomment

if False:
  print('Hello') # yes you can do it at the end of a line
  you can technically put if False around code you dont want it to run,
  but that would mean it has to have correct syntax,
  and would not be good for readability.

Example 2: comment all selected lines in python

Select relevant lines to be commented, then use ctrl+/