code: def create_subtask(client, task_id, title, completed=False):
      ''' Creates a subtask with the given title under the task with the given ID '''
      _check_title_length(title, client.api)
      data = {
              'task_id' : int(task_id) if task_id else None,
              'title' : title,
              'completed' : completed,
              }
      data = { key: value for key, value in data.items() if value is not None }
      response = client.authenticated_request(client.api.Endpoints.SUBTASKS, 'POST', data=data)
      return response.json(f create_subtask(client, task_id, title, completed=False):
      ''' Creates a subtask with the given title under the task with the given ID '''
      _check_title_length(title, client.api)
      data = {
              'task_id' : int(task_id) if task_id else None,
              'title' : title,
              'completed' : completed,
              }
      data = { key: value for key, value in data.items() if value is not None }
      response = client.authenticated_request(client.api.Endpoints.SUBTASKS, 'POST', data=data)
      return response.json()
docs: Creates a subtask with the given title under the task with the given ID