def METHOD_NAME(self):
    """ This returns a list of message names that would cause this
        process to start. """
    message_names = []
    messages = self.xpath("//bpmn:message")
    message_event_definitions = self.xpath(
        "//bpmn:startEvent/bpmn:messageEventDefinition")
    for message_event_definition in message_event_definitions:
        message_model_identifier = message_event_definition.attrib.get(
            "messageRef"
        )
        if message_model_identifier is None:
            raise ValidationException(
                "Could not find messageRef from message event definition: {message_event_definition}"
            )
        # Convert the id into a Message Name
        message_name = next((m for m in messages if m.attrib.get('id') == message_model_identifier), None)
        message_names.append(message_name.attrib.get('name'))
    return message_names