Will pose the question to the user and keep asking them until they
provide an answer that starts with either a 'y' or an 'n', at which
point it will return True if it was a 'y'.
response = input("%s (y/n): " % question).lower()
if re.match(r'^[yn]', response) is not None:
print("Incorrect option '%s'" % response)
return response == 'y'