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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 get(self, workflow_id):
 """ Returns the document for the given workflow id. Args: workflow_id (str):
 The id of the document that represents a workflow run. Raises: DataStoreNotConnected: If the data store is not connected to the server. Returns: DataStoreDocument: The document for the given workflow id. """

        try:
            db = self._client[self.database]
            fs = GridFSProxy(GridFS(db.unproxied_object))
            return DataStoreDocument(db[WORKFLOW_DATA_COLLECTION_NAME], fs, workflow_id)

        except ConnectionFailure:
            raise DataStoreNotConnected()