code: def uninstall_visa_handler(self, session, event_type, handler, user_handle=None):
          
          for ndx, element in enumerate(self.handlers[session]):
              if element[0] is handler and element[1] is user_handle and element[4] == event_type:
                  del self.handlers[session][ndx]
                  break
          else:
              raise errors.UnknownHandler(event_type, handler, user_handle)
          self.uninstall_handler(session, event_type,  element[2], user_handle)
docs: Uninstalls handlers for events.
  
          :param session: Unique logical identifier to a session.
          :param event_type: Logical event identifier.
          :param handler: Interpreted as a valid reference to a handler to be uninstalled by a client application.
          :param user_handle: The user handle (ctypes object or None) returned by install_visa_handler.