parameters: (self, f)
return_statement: return f
docstring: Registers the function `f` as gradient function for `op_type`.
docstring_summary: Registers the function `f` as gradient function for `op_type`.
docstring_tokens: Registers the function f as gradient function for op_type .
function: def __call__(self, f):
      """Registers the function `f` as gradient function for `op_type`."""
      _gradient_registry.register(f, self._op_type)
      return f
function_tokens: def __call__ ( self , f ) : _gradient_registry . register ( f , self . _op_type ) return f