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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _update_info(self):
 """ Call parent method and make sure this is in fact a table HDU. Set some convenience data. """

        super(TableHDU, self)._update_info()
        if self._info['hdutype'] == IMAGE_HDU:
            mess = "Extension %s is not a Table HDU" % self.ext
            raise ValueError(mess)
        if 'colinfo' in self._info:
            self._colnames = [i['name'] for i in self._info['colinfo']]
            self._colnames_lower = [
                i['name'].lower() for i in self._info['colinfo']]
            self._ncol = len(self._colnames)