sanitize a name/namespace record before returning it.
        * canonicalize it
        * remove quirk fields

def sanitize_rec(self, rec):
        """
        sanitize a name/namespace record before returning it.
        * canonicalize it
        * remove quirk fields
        """
        opcode = rec['opcode']
        canonical_op = op_canonicalize(opcode, rec)

        # don't return internally-used quirk fields
        quirk_fields = op_get_quirk_fields(opcode)
        for f in quirk_fields:
            if f in canonical_op:
                del canonical_op[f]

        # if we have a 'token_fee', make it a string
        if 'token_fee' in canonical_op:
            canonical_op['token_fee'] = str(canonical_op['token_fee'])

        canonical_op['opcode'] = opcode
        return canonical_op