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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 init_from_datastore(self):
 """Initializes data by reading it from the datastore."""

    self._data = {}
    client = self._datastore_client
    for entity in client.query_fetch(kind=KIND_CLASSIFICATION_BATCH):
      class_batch_id = entity.key.flat_path[-1]
      self.data[class_batch_id] = dict(entity)