code: def get_transaction(self, transaction_id):
          
          payload = self._get_data_by_id(
              transaction_id, 'commit_store_get_transaction')
  
          txn = Transaction()
          txn.ParseFromString(payload)
  
          return txn
docs: Returns a Transaction object from the block store by its id.
  
          Params:
              transaction_id (str): The header_signature of the desired txn
  
          Returns:
              Transaction: The specified transaction
  
          Raises:
              ValueError: The transaction is not in the block store