Fixed read_attrs if there is only a single attribute

wrappers/classes/modelverse.xml

@@ -1056,7 +1056,7 @@
                         <transition cond="self.expect_response_partial('Success: ', pop=False)" target="../../wait_for_action/history">
                             <script>
                                 response = self.responses.pop(0).split(": ", 1)[1].strip()
-                                if "\n" in response:
+                                if " : " in response:
                                     values = {line.split(" : ", 1)[0]: line.split(" : ", 1)[1] for line in response.split("\n")}
                                     values = {key: json.loads(values[key].split(" = ", 1)[1]) for key in values}
                                 else: