How to use the ofxparse.mcc.codes.get function in ofxparse

raise OfxParserException(six.u("No FIT id (a required field)"))
        else:
            raise OfxParserException(six.u("Missing FIT id (a required \
                                     field)"))

        sic_tag = txn_ofx.find('sic')
        if hasattr(sic_tag, 'contents'):
            try:
                transaction.sic = sic_tag.contents[0].strip()
            except IndexError:
                raise OfxParserException(six.u("Empty transaction Standard \
                                         Industry Code (SIC)"))

        if transaction.sic is not None and transaction.sic in mcc.codes:
            try:
                transaction.mcc = mcc.codes.get(transaction.sic, '').get('combined \
                    description')
            except IndexError:
                raise OfxParserException(six.u("Empty transaction Merchant Category \
                    Code (MCC)"))
            except AttributeError:
                if cls.fail_fast:
                    raise

        checknum_tag = txn_ofx.find('checknum')
        if hasattr(checknum_tag, 'contents'):
            try:
                transaction.checknum = checknum_tag.contents[0].strip()
            except IndexError:
                raise OfxParserException(six.u("Empty Check (or other reference) \
                    number"))