new_contents: import logging
  
  from timetracker import models
  
  
  def create_activity(title='Test Title', start_time=None, end_time=None,
                      logger=None):
      """Create an `Activity` instance for testing purposes.
  
      The fields are given default values so that instances can be easily
      created for testing purposes.
  
      Args:
          title (str): The title of the activity.
          start_time (datetime,optional): The time the activity started.
              Defaults to the current time if not provided.
          end_time (datetime,optional): The time the activity ended.
              Defaults to `None` if not provided.
  
      Returns:
          Activity: An `Activity` instance with the given parameters.
      """
      logger = logger or logging.getLogger(__name__)
  
      kwargs = {
          'title': title,
      }
  
      if start_time is not None:
          kwargs['start_time'] = start_time
  
      if end_time is not None:
          kwargs['end_time'] = end_time
  
      logger.debug("Creating new test activity with params title: %s, "
                   "start_time: %s, end_time: %s", title, start_time, end_time)
  
      return models.Activity.objects.create(**kwargs)
  
subject: Add testing utility to create activities.