def _padding_model_number(number, max_num):
    '''
    This method returns a zero-front padded string

    It makes out of str(45) -> '0045' if 999 < max_num < 10000. This is
    meant to work for reasonable integers (maybe less than 10^6).

    Parameters
    ----------
    number : integer
        number that the string should represent.
    max_num : integer
        max number of cycle list, implies how many 0s have be padded

    '''

    cnum = str(number)
    clen = len(cnum)

    cmax = int(log10(max_num)) + 1

    return (cmax - clen)*'0' + cnum
This method returns a zero-front padded string

    It makes out of str(45) -> '0045' if 999 < max_num < 10000. This is
    meant to work for reasonable integers (maybe less than 10^6).

    Parameters
    ----------
    number : integer
        number that the string should represent.
    max_num : integer
        max number of cycle list, implies how many 0s have be padded