''' Purpose: repeatedly prompt the user until they reply with a yes
        or no. The case of the letters do not matter.
'''

looking_for_a_yes_or_no = True

# Generally start off the test expression as True so you can
# set it to False later on when you get what you want and
# you wanna be done with the while loop. :)

# This variable is just a variable that stores the value of a variable.
# We set it to True so that we can set it to false later once
# we find what we're looking for! Think of it kindaaa like a light switch.
# Turning the light switch on while you look for something and then off
# when you find it and finish and stop looking.

while ( looking_for_a_yes_or_no == True ) : # Sooo if you do it this way
   # there's no need for line 6.

   reply = input( 'Enter (yes / no): ' )

   reply = reply.lower().strip()

   # When you call multiple string functions on the same stirng, make sure that
   # all your functions are returning strings when you call it on them.
   # reply.lower() returns a string so we can then call .strip() on that
   # string.

   if ( reply in [ 'yes', 'no' ]): # if

       looking_for_a_yes_or_no = False

# So remember that indentation is whenever an action is part of a
# larger for or if or while statement.
# So everything indented under the while is done for each time we
# run through the while loop.
# So in this example, in the while loop, what are we doing?
   # Getting an input, stripping/lowercaseing it, and then checking to see
   # if its yes or no and then setting the looking_for_a_yes_or_no variable
   # to be false to signify heyyy we found it so stop the while loop (
   # by setting the variable to False) because it's not True anymore! So it stops.
   # ;we don't have to repeat this process in the while loop again.

   print( reply )