parameters: (self, loop)
docstring: Attach the watcher to an event loop.
  
          If the watcher was previously attached to an event loop, then it is
          first detached before attaching to the new loop.
  
          Note: loop may be None.
docstring_summary: Attach the watcher to an event loop.
docstring_tokens: Attach the watcher to an event loop .
function: def attach_loop(self, loop):
          """Attach the watcher to an event loop.
  
          If the watcher was previously attached to an event loop, then it is
          first detached before attaching to the new loop.
  
          Note: loop may be None.
          """
          raise NotImplementedError()
function_tokens: def attach_loop ( self , loop ) : raise NotImplementedError ( )