@staticmethod
def get_group(match, group):
    """Get a group from a regular expression match object if it exists.

        Parameters
        ----------
        match : `_sre.SRE_Match`
            Regular expression match object.
        group : `str` or `int`
            Group name or index.

        Returns
        -------
        `str` or `None`
        """
    try:
        return match.group(group)
    except IndexError:
        return None
