def filter_by(self, **kwargs):
        """
        Apply the given filtering criterion to a copy of this Query, using
        keyword expressions.
        """
        query = self._copy()
        for field, value in kwargs.items():
            query.domain.append(
                (field, '=', value)
            )
        return query
def filter_by ( self , ** kwargs ) : query = self . _copy ( ) for field , value in kwargs . items ( ) : query . domain . append ( ( field , '=' , value ) ) return query
Apply the given filtering criterion to a copy of this Query, using
        keyword expressions.