old_contents: # Copyright 2017, Google Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  """Private helpers for futures."""
  
  import logging
  import threading
  
  
  _LOGGER = logging.getLogger(__name__)
  
  
  def start_daemon_thread(*args, **kwargs):
      """Starts a thread and marks it as a daemon thread."""
      thread = threading.Thread(*args, **kwargs)
      thread.daemon = True
      thread.start()
      return thread
  
  
  def safe_invoke_callback(callback, *args, **kwargs):
      """Invoke a callback, swallowing and logging any exceptions."""
      # pylint: disable=bare-except
      # We intentionally want to swallow all exceptions.
      try:
          return callback(*args, **kwargs)
      except:
          _LOGGER.exception('Error while executing Future callback.')
  
new_contents: # Copyright 2017, Google Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  """Private helpers for futures."""
  
  import logging
  import threading
  
  
  _LOGGER = logging.getLogger(__name__)
  
  
  def start_daemon_thread(*args, **kwargs):
      """Starts a thread and marks it as a daemon thread."""
      thread = threading.Thread(*args, **kwargs)
      thread.daemon = True
      thread.start()
      return thread
  
  
  def safe_invoke_callback(callback, *args, **kwargs):
      """Invoke a callback, swallowing and logging any exceptions."""
      # pylint: disable=bare-except
      # We intentionally want to swallow all exceptions.
      try:
          return callback(*args, **kwargs)
      except Exception:
          _LOGGER.exception('Error while executing Future callback.')
  
subject: Fix bare except (#4250)