parameters: (self, node_name, device_name=None)
return_statement: return watch_keys
docstring: Get all tensor watch keys of given node according to partition graphs.
  
      Args:
        node_name: (`str`) name of the node.
        device_name: (`str`) name of the device. If there is only one device or if
          node_name exists on only one device, this argument is optional.
  
      Returns:
        (`list` of `str`) all debug tensor watch keys. Returns an empty list if
          the node name does not correspond to any debug watch keys.
  
      Raises:
        `LookupError`: If debug watch information has not been loaded from
          partition graphs yet.
docstring_summary: Get all tensor watch keys of given node according to partition graphs.
docstring_tokens: Get all tensor watch keys of given node according to partition graphs .
function: def debug_watch_keys(self, node_name, device_name=None):
      """Get all tensor watch keys of given node according to partition graphs.
  
      Args:
        node_name: (`str`) name of the node.
        device_name: (`str`) name of the device. If there is only one device or if
          node_name exists on only one device, this argument is optional.
  
      Returns:
        (`list` of `str`) all debug tensor watch keys. Returns an empty list if
          the node name does not correspond to any debug watch keys.
  
      Raises:
        `LookupError`: If debug watch information has not been loaded from
          partition graphs yet.
      """
  
      try:
        device_name = self._infer_device_name(device_name, node_name)
      except ValueError:
        return []
  
      if node_name not in self._debug_watches[device_name]:
        return []
  
      watch_keys = []
      for watched_slot in self._debug_watches[device_name][node_name]:
        debug_ops = self._debug_watches[device_name][node_name][watched_slot]
        for debug_op in debug_ops:
          watch_keys.append(
              _get_tensor_watch_key(node_name, watched_slot, debug_op))
  
      return watch_keys
function_tokens: def debug_watch_keys ( self , node_name , device_name = None ) : try : device_name = self . _infer_device_name ( device_name , node_name ) except ValueError : return [ ] if node_name not in self . _debug_watches [ device_name ] : return [ ] watch_keys = [ ] for watched_slot in self . _debug_watches [ device_name ] [ node_name ] : debug_ops = self . _debug_watches [ device_name ] [ node_name ] [ watched_slot ] for debug_op in debug_ops : watch_keys . append ( _get_tensor_watch_key ( node_name , watched_slot , debug_op ) ) return watch_keys