@staticmethod
def colorize(text, color_number=None):
    """Return colorized version of 'text', with terminal color 'color_number' (31, 32...).
        Return bare text if 'color_number' is None.
        """
    if color_number is None:
        return text
    return '\x1b[{n}m{t}\x1b[0m'.format(t=text, n=color_number)
