How to use the napari.utils.event.Event function in napari

def __init__(
        self, title='napari', ndisplay=2, order=None, axis_labels=None
    ):
        super().__init__()

        self.events = EmitterGroup(
            source=self,
            auto_connect=True,
            status=Event,
            help=Event,
            title=Event,
            interactive=Event,
            cursor=Event,
            reset_view=Event,
            active_layer=Event,
            palette=Event,
            grid=Event,
            layers_change=Event,
        )

        self.dims = Dims(
            ndim=None, ndisplay=ndisplay, order=order, axis_labels=axis_labels
        )

        self.layers = LayerList()

visible=True,
    ):

        super().__init__(
            2,
            name=name,
            metadata=metadata,
            scale=scale,
            translate=translate,
            opacity=opacity,
            blending=blending,
            visible=visible,
        )

        # events for non-napari calculations
        self.events.add(length=Event, edge_width=Event, edge_color=Event)

        # Save the vector style params
        self._edge_width = edge_width
        self._edge_color = edge_color
        self._colors = get_color_names()

        self._mesh_vertices = np.empty((0, 2))
        self._mesh_triangles = np.empty((0, 3), dtype=np.uint32)

        # Data containing vectors in the currently viewed slice
        self._data_view = np.empty((0, 2, 2))
        self._displayed_stored = []
        self._view_vertices = []
        self._view_faces = []

        # length attribute

def __init__(
        self, title='napari', ndisplay=2, order=None, axis_labels=None
    ):
        super().__init__()

        self.events = EmitterGroup(
            source=self,
            auto_connect=True,
            status=Event,
            help=Event,
            title=Event,
            interactive=Event,
            cursor=Event,
            reset_view=Event,
            active_layer=Event,
            palette=Event,
            grid=Event,
            layers_change=Event,
        )

        self.dims = Dims(
            ndim=None, ndisplay=ndisplay, order=order, axis_labels=axis_labels
        )

        self.layers = LayerList()

        self._status = 'Ready'
        self._help = ''
        self._title = title
        self._cursor = 'standard'

if name in self._emitters:
                raise ValueError(
                    "EmitterGroup already has an emitter named '%s'" % name
                )
            elif hasattr(self, name):
                raise ValueError(
                    "The name '%s' cannot be used as an emitter; "
                    "it is already an attribute of EmitterGroup" % name
                )

        # add each emitter specified in the keyword arguments
        for name, emitter in kwargs.items():
            if emitter is None:
                emitter = Event

            if inspect.isclass(emitter) and issubclass(emitter, Event):
                emitter = EventEmitter(
                    source=self.source, type=name, event_class=emitter
                )
            elif not isinstance(emitter, EventEmitter):
                raise Exception(
                    'Emitter must be specified as either an '
                    'EventEmitter instance or Event subclass. '
                    '(got %s=%s)' % (name, emitter)
                )

            # give this emitter the same source as the group.
            emitter.source = self.source

            setattr(self, name, emitter)
            self._emitters[name] = emitter

self._scale_view = np.ones(ndim)
        self._translate_view = np.zeros(ndim)
        self._translate_grid = np.zeros(ndim)
        self.coordinates = (0,) * ndim
        self._position = (0,) * self.dims.ndisplay
        self.is_pyramid = False
        self._editable = True

        self._thumbnail_shape = (32, 32, 4)
        self._thumbnail = np.zeros(self._thumbnail_shape, dtype=np.uint8)
        self._update_properties = True
        self._name = ''
        self.events = EmitterGroup(
            source=self,
            auto_connect=True,
            refresh=Event,
            set_data=Event,
            blending=Event,
            opacity=Event,
            visible=Event,
            select=Event,
            deselect=Event,
            scale=Event,
            translate=Event,
            data=Event,
            name=Event,
            thumbnail=Event,
            status=Event,
            help=Event,
            interactive=Event,
            cursor=Event,
            cursor_size=Event,

def __init__(
        self, title='napari', ndisplay=2, order=None, axis_labels=None
    ):
        super().__init__()

        self.events = EmitterGroup(
            source=self,
            auto_connect=True,
            status=Event,
            help=Event,
            title=Event,
            interactive=Event,
            cursor=Event,
            reset_view=Event,
            active_layer=Event,
            palette=Event,
            grid=Event,
            layers_change=Event,
        )

        self.dims = Dims(
            ndim=None, ndisplay=ndisplay, order=order, axis_labels=axis_labels
        )

        self.layers = LayerList()

        self._status = 'Ready'

super().__init__(
            ndim,
            name=name,
            metadata=metadata,
            scale=scale,
            translate=translate,
            blending=blending,
            visible=visible,
        )

        self.events.add(
            mode=Event,
            edge_width=Event,
            edge_color=Event,
            face_color=Event,
            highlight=Event,
        )

        self._display_order_stored = []
        self._ndisplay_stored = self.dims.ndisplay
        self.dims.clip = False

        # The following shape properties are for the new shapes that will
        # be drawn. Each shape has a corresponding property with the
        # value for itself
        if np.isscalar(edge_width):
            self._edge_width = edge_width
        else:
            self._edge_width = 1

        if type(edge_color) is str:
            self._edge_color = edge_color

interpolation='nearest',
            rendering='mip',
            name=name,
            metadata=metadata,
            scale=scale,
            translate=translate,
            opacity=opacity,
            blending=blending,
            visible=visible,
        )

        self.events.add(
            mode=Event,
            n_dimensional=Event,
            contiguous=Event,
            brush_size=Event,
            selected_label=Event,
        )

        self._data_raw = np.zeros((1,) * self.dims.ndisplay)
        self._n_dimensional = False
        self._contiguous = True
        self._brush_size = 10
        self._last_cursor_coord = None

        self._selected_label = 0
        self._selected_color = None

        self._mode = Mode.PAN_ZOOM
        self._mode_history = self._mode
        self._status = self.mode
        self._help = 'enter paint or fill mode to edit labels'

super().__init__(
            ndim,
            name=name,
            metadata=metadata,
            scale=scale,
            translate=translate,
            opacity=opacity,
            blending=blending,
            visible=visible,
        )

        self.events.add(
            mode=Event,
            size=Event,
            edge_width=Event,
            face_color=Event,
            edge_color=Event,
            symbol=Event,
            n_dimensional=Event,
            highlight=Event,
        )
        self._colors = get_color_names()

        # Save the point coordinates
        self._data = data
        self.dims.clip = False

        # Save the point style params
        self.symbol = symbol
        self._n_dimensional = n_dimensional
        self.edge_width = edge_width