#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Mon Sep 24 14:35:46 2018

@author: vicky
"""

def is_isogram(string):
    string.lower()
    ''.join(sorted(string))
    while isogram = True:
    for i in string:
        string.pop(i)
        if i in string:
            isogram = True
        else: 
            isogram = False
    
    return 
        
            
    

is_isogram("rudy")