Create a dictionary containing the excel columns name

columns.py

import string
from copy import deepcopy


def excel_columns(max_lenght=None):
    """
     This method maps the excel columns names with a simple index,
     Ex:
         {0: 'A', 1: 'B', 2: 'C', 3: 'D', 4: 'E', ...
         26: 'AA', 27: 'AB', 28: 'AC', 29: 'AD', 30: 'AE', ...
         1378: 'AAA', 1379: 'AAB', 1380: 'AAC', 1381: 'AAD', 1382: 'AAE',... }
     Returns: dict
    """
    class BrakeAllLoops(Exception):
        pass

    letras = [x for x in string.uppercase]
    result = [x for x in string.uppercase]
    if not max_lenght:
        # This number is for the result to have from A to ZZZ
        max_lenght = 18954
    else:
        try:
            max_lenght = int(max_lenght)
        except ValueError:
            raise TypeError("max_length parameter must be a integer number")
    # 'deepcopy' is for the loop not to be changed when adding data to
    # the result variable
    copia = deepcopy(result)
    try:
        while True:
            for atual in copia:
                for letra in letras:
                    result.append(atual + letra)
                    if len(result) >= max_lenght:
                        raise BrakeAllLoops()
            copia = deepcopy(result)
    except BrakeAllLoops:
        pass

    return dict(enumerate(result))

print excel_columns()