fix(samples): batch_update() results processing error (#484)

* fix(samples): batch_update() results processing error * fix the comment * minor fix Co-authored-by: larkee <31196561+larkee@users.noreply.github.com>

Author: Ilya Gurov

samples/samples/snippets.py

@@ -1511,6 +1511,8 @@ def delete_data_with_partitioned_dml(instance_id, database_id):
 def update_with_batch_dml(instance_id, database_id):
  """Updates sample data in the database using Batch DML. """
  # [START spanner_dml_batch_update]
+ from google.rpc.code_pb2 import OK
+
  # instance_id = "your-spanner-instance"
  # database_id = "your-spanner-db-id"
 
@@ -1531,7 +1533,13 @@ def update_with_batch_dml(instance_id, database_id):
  )
 
  def update_albums(transaction):
- row_cts = transaction.batch_update([insert_statement, update_statement])
+ status, row_cts = transaction.batch_update([insert_statement, update_statement])
+
+ if status.code != OK:
+ # Do handling here.
+ # Note: the exception will still be raised when
+ # `commit` is called by `run_in_transaction`.
+ return
 
  print("Executed {} SQL statements using Batch DML.".format(len(row_cts)))