code: def _add_deprecated_function_notice_to_docstring(doc, date, instructions):
      
  
      if instructions:
          deprecation_message = """
              .. warning::
                  **THIS FUNCTION IS DEPRECATED:** It will be removed after %s.
                  *Instructions for updating:* %s.
          """ % (('in a future version' if date is None else ('after %s' % date)), instructions)
  
      else:
          deprecation_message = """
              .. warning::
                  **THIS FUNCTION IS DEPRECATED:** It will be removed after %s.
          """ % (('in a future version' if date is None else ('after %s' % date)))
  
      main_text = [deprecation_message]
  
      return _add_notice_to_docstring(doc, 'DEPRECATED FUNCTION', main_text)
docs: Adds a deprecation notice to a docstring for deprecated functions.