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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_rtm(cls, raw_event: MutableMapping) -> "Event": """ Create an event with data coming from the RTM API. If the event type is a message a :class:`slack.events.Message` is returned. Args: raw_event: JSON decoded data from the RTM API Returns: :class:`slack.events.Event` or :class:`slack.events.Message` """

        if raw_event["type"].startswith("message"):
            return Message(raw_event)
        else:
            return Event(raw_event)