bug in my code

[sunnysude]

You are getting an error, because you are telling Python to generate an error, so Python says "okee dokee here's an error"

If you don't want that, try something like:

   elif not cat.isalpha():
     print("not alpha")
     break

Just a matter of semantics, but your response "Argument should be a string", is not really accurate,  since at the beginning of your function you are converting every thing to a string.

according to the assignment question am suppose to raise a type error here is the full question

Write a program that checks if a word supplied as the argument is an Isogram. An Isogram is a word in which no letter occurs more than once.

Create a method called is_isogram that takes one argument, a word to test if it's an isogram. This method should return a tuple of the word and a boolean indicating whether it is an isogram.

If the argument supplied is an empty string, return the argument and False: (argument, False). If the argument supplied is not a string, raise a TypeError with the message 'Argument should be a string'.