def _meta_schema_factory(self, columns, model, class_mixin):
_model = model<EOL>if columns:<EOL><INDENT>class MetaSchema(ModelSchema, class_mixin):<EOL><INDENT>class Meta:<EOL><INDENT>model = _model<EOL>fields = columns<EOL>strict = True<EOL>sqla_session = self.datamodel.session<EOL><DEDENT><DEDENT><DEDENT>else:<EOL><INDENT>class MetaSchema(ModelSchema, class_mixin):<EOL><INDENT>class Meta:<EOL><INDENT>model = _model<EOL>strict = True<EOL>sqla_session = self.datamodel.session<EOL><DEDENT><DEDENT><DEDENT>return MetaSchema<EOL>
Creates ModelSchema marshmallow-sqlalchemy

:param columns: a list of columns to mix
:param model: Model
:param class_mixin: a marshamallow Schema to mix
:return: ModelSchema