def lookup(self, name):
if name in self.attributes():<EOL><INDENT>return getattr(self, IMPL_PREFIX + name)<EOL><DEDENT>raise exceptions.AttributeInferenceError(target=self._instance, attribute=name)<EOL>
Look up the given *name* in the current model

        It should return an AST or an interpreter object,
        but if the name is not found, then an AttributeInferenceError will be raised.