class_docstr: Fake for datastore transaction.
  
  See https://cloud.google.com/datastore/docs/concepts/transactions
  for details of how transactions work in Cloud Datastore.
class_docstr_tok: ["Fake","for","datastore","transaction",".","See","https",":","\/\/cloud.google.com\/datastore\/docs\/concepts\/transactions","for","details","of","how","transactions","work","in","Cloud","Datastore","."]
code: def __exit__(self, exc_type, exc_value, traceback):
      if exc_type is None:
          self.commit()
      else:
          self.rollback()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  from io import StringIO
  import six
label_desc: Use image node_id 10 for calling the FakeDatastoreClientTransaction obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_value, traceback) without return types