def install_visa_handler(self, session, event_type, handler, user_handle=None):
        """Installs handlers for event callbacks.

        :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 installed by a client application.
        :param user_handle: A value specified by an application that can be used for identifying handlers
                            uniquely for an event type.
        :returns: user handle (a ctypes object)
        """
        try:
            new_handler = self.install_handler(session, event_type, handler, user_handle)
        except TypeError as e:
            raise errors.VisaTypeError(str(e))

        self.handlers[session].append(new_handler + (event_type,))
        return new_handler[1]
def install_visa_handler ( self , session , event_type , handler , user_handle = None ) : try : new_handler = self . install_handler ( session , event_type , handler , user_handle ) except TypeError as e : raise errors . VisaTypeError ( str ( e ) ) self . handlers [ session ] . append ( new_handler + ( event_type , ) ) return new_handler [ 1 ]
Installs handlers for event callbacks.

        :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 installed by a client application.
        :param user_handle: A value specified by an application that can be used for identifying handlers
                            uniquely for an event type.
        :returns: user handle (a ctypes object)