'Transform the output file into any Mace4 ``interpformat`` format.
:param format: Output format for displaying models.
:type format: str'

def _transform_output(self, valuation_str, format):

    if (format in ['standard', 'standard2', 'portable', 'tabular', 'raw', 'cooked', 'xml', 'tex']):
        return self._call_interpformat(valuation_str, [format])[0]
    else:
        raise LookupError('The    specified    format    does    not    exist')
