@staticmethod
def _get_variation_id(value, capital=False):
    """ Convert an integer value to a character. a-z then double aa-zz etc
        Args:
            value (int): integer index we're looking up
            capital (bool): whether we convert to capitals or not
        Returns (str): alphanumeric representation of the index
        """
    value = int(value)
    base_power = base_start = base_end = 0
    while value >= base_end:
        base_power += 1
        base_start = base_end
        base_end += pow(26, base_power)
    base_index = value - base_start
    alphas = ['a'] * base_power
    for index in range(base_power - 1, -1, -1):
        alphas[index] = chr(int(97 + base_index % 26))
        base_index /= 26
    characters = ''.join(alphas)
    return characters.upper() if capital else characters
