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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 _create_and_save_state(cls, mapreduce_spec, _app):
 """Save mapreduce state to datastore. Save state to datastore so that UI can see it immediately. Args: mapreduce_spec: model.MapreduceSpec, _app: app id if specified. None otherwise. Returns: The saved Mapreduce state. """

    state = model.MapreduceState.create_new(mapreduce_spec.mapreduce_id)
    state.mapreduce_spec = mapreduce_spec
    state.active = True
    state.active_shards = 0
    if _app:
      state.app_id = _app
    config = util.create_datastore_write_config(mapreduce_spec)
    state.put(config=config)
    return state