#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Napisz funkcję leet_speak, która podmienia w podanym napisie niektóre litery
na podobnie wyglądające cyfry: 'e' na '3', 'l' na '1', 'o' na '0', 't' na '7'.
Np. leet('leet') powinno zwrócić '1337'.
"""


def leet_speak(text):
    letterList = list(text)
    x = 0
    for i in letterList:
        if i == 'e':
            letterList[x] = '3'
        elif i == 'l':
            letterList[x] = '1'
        elif i == 'o':
            letterList[x] = '0'
        elif i == 't':
            letterList[x] = '7'
        x += 1
    finalOutput = ''.join(letterList)
    return finalOutput


def tests(f):
    inputs = [['leet'], ['do not want']]
    outputs = ['1337', 'd0 n07 wan7']

    for input, output in zip(inputs, outputs):
        if f(*input) != output:
            return "ERROR: {}!={}".format(f(*input), output)
            break
    return "TESTS PASSED"

if __name__ == "__main__":
    print(tests(leet_speak))