old_contents: """:mod:`cliche.services` --- Interfacing external services
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  How to add a new external service
  ---------------------------------
  
  In order to add a new service to cliche, you must create a subpackage under
  :data:`cliche.services` and expose some methods referring to interfaces,
  using :file:`__init__.py`.
  
  Interfaces needed to be exposed
  -------------------------------
  
  - :func:`sync()`: Method to delay a main crawling task to the queue. It should
    be decorated with :code:`@app.task` to be defined as a celery app worker
    task.
  
  Example :file:`__init__.py`
  ---------------------------
  
  .. sourcecode:: python
  
     from .crawler import crawl as sync  # noqa
  
  
     __all__ = 'sync',
  
  Note that you will need the import lines annotated with :code:`# noqa` because
  otherwise :program:`flake8` will consider it as unused import.
  
  """
  
new_contents: """:mod:`cliche.services` --- Interfacing external services
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  How to add a new external service
  ---------------------------------
  
  In order to add a new service to cliche, you must create a subpackage under
  :data:`cliche.services` and expose some methods referring to interfaces,
  using :file:`__init__.py`.
  
  Interfaces needed to be exposed
  -------------------------------
  
  - :func:`sync()`: Method to delay a main crawling task to the queue. It should
    be decorated with :code:`@app.task` to be defined as a celery app worker
    task. It should have no arguments and no return. Every output should be made
    as a log to celery logger.
  
  Example :file:`__init__.py`
  ---------------------------
  
  .. sourcecode:: python
  
     from .crawler import crawl as sync  # noqa
  
  
     __all__ = 'sync',
  
  Note that you will need the import lines annotated with :code:`# noqa` because
  otherwise :program:`flake8` will consider it as unused import.
  
  """
  
subject: Add some details to docs