parameters: (self, handler)
docstring: Register an object to receive error-message events.
docstring_summary: Register an object to receive error-message events.
docstring_tokens: Register an object to receive error - message events .
function: def setErrorHandler(self, handler):
          "Register an object to receive error-message events."
          self._err_handler = handler
function_tokens: def setErrorHandler ( self , handler ) : self . _err_handler = handler