code: def enable_event(library, session, event_type, mechanism, context=None):
      
      if context is None:
          context = constants.VI_NULL
      elif context != constants.VI_NULL:
          warnings.warn('In enable_event, context will be set VI_NULL.')
          context = constants.VI_NULL  # according to spec VPP-4.3, section 3.7.3.1
      return library.viEnableEvent(session, event_type, mechanism, context)
docs: Enable event occurrences for specified event types and mechanisms in a session.
  
      Corresponds to viEnableEvent function of the VISA library.
  
      :param library: the visa library wrapped by ctypes.
      :param session: Unique logical identifier to a session.
      :param event_type: Logical event identifier.
      :param mechanism: Specifies event handling mechanisms to be enabled.
                        (Constants.VI_QUEUE, .VI_HNDLR, .VI_SUSPEND_HNDLR)
      :param context:
      :return: return value of the library call.
      :rtype: :class:`pyvisa.constants.StatusCode`