'Method called by the parse method in the parent class.'

def _parse_internal(self, hdukeys, keywords, compressed):

    tablerows = []
    for hdu in hdukeys:
        try:
            for card in self._get_cards(hdu, keywords, compressed):
                tablerows.append({'filename': self.filename, 'hdu': hdu, 'keyword': card.keyword, 'value': str(card.value)})
        except ExtensionNotFoundException:
            pass
    if tablerows:
        from .... import table
        return table.Table(tablerows)
    return None
