How to use the enaml.qt.QtCore.Signal function in enaml

class QDockWindowButtons(QFrame):
    """ A custom QFrame which provides the buttons for a QDockWindow.

    """
    #: A signal emitted when the maximize button is clicked.
    maximizeButtonClicked = Signal(bool)

    #: A signal emitted when the restore button is clicked.
    restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is closed.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: Do not show any buttons in the widget.
    NoButtons = 0x0

    #: Show the maximize button in the widget.
    MaximizeButton = 0x1

    #: Show the restore button in the widget.
    RestoreButton = 0x2

    #: Show the close button in the widget.
    CloseButton = 0x4

    #: Show the link button in the widget.
    LinkButton = 0x8

""" A concrete implementation of IDockTitleBar.

    This class serves as the default title bar for a QDockItem.

    """
    #: A signal emitted when the maximize button is clicked.
    maximizeButtonClicked = Signal(bool)

    #: A signal emitted when the restore button is clicked.
    restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is clicked.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: A signal emitted when the pin button is toggled.
    pinButtonToggled = Signal(bool)

    #: A signal emitted when the title is edited by the user.
    titleEdited = Signal(str)

    #: A signal emitted when the empty area is left double clicked.
    leftDoubleClicked = Signal(QPoint)

    #: A signal emitted when the empty area is right clicked.
    rightClicked = Signal(QPoint)

    def __init__(self, parent=None):
        """ Initialize a QDockTitleBar.

restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is clicked.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: A signal emitted when the pin button is toggled.
    pinButtonToggled = Signal(bool)

    #: A signal emitted when the title is edited by the user.
    titleEdited = Signal(unicode)

    #: A signal emitted when the title bar is left double clicked.
    leftDoubleClicked = Signal(QPoint)

    #: A signal emitted when the title bar is right clicked.
    rightClicked = Signal(QPoint)

    #: Do not show any buttons in the title bar.
    NoButtons = 0x0

    #: Show the maximize button in the title bar.
    MaximizeButton = 0x1

    #: Show the restore button in the title bar.
    RestoreButton = 0x2

    #: Show the close button in the title bar.
    CloseButton = 0x4

----------
        hidden : bool
            True if the title bar should be hidden, False otherwise.

        """
        raise NotImplementedError


class QDockTitleBar(QFrame, IDockTitleBar):
    """ A concrete implementation of IDockTitleBar.

    This class serves as the default title bar for a QDockItem.

    """
    #: A signal emitted when the maximize button is clicked.
    maximizeButtonClicked = Signal(bool)

    #: A signal emitted when the restore button is clicked.
    restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is clicked.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: A signal emitted when the pin button is toggled.
    pinButtonToggled = Signal(bool)

    #: A signal emitted when the title is edited by the user.
    titleEdited = Signal(str)

#: A signal emitted when the title is edited by the user. This
    #: signal is proxied from the current dock item title bar.
    titleEdited = Signal(str)

    #: A signal emitted when the empty area is left double clicked.
    #: This signal is proxied from the current dock item title bar.
    titleBarLeftDoubleClicked = Signal(QPoint)

    #: A signal emitted when the empty area is right clicked. This
    #: signal is proxied from the current dock item title bar.
    titleBarRightClicked = Signal(QPoint)

    #: A signal emitted when the item is alerted. The payload is the
    #: new alert level. An empty string indicates no alert.
    alerted = Signal(str)

    def __init__(self, parent=None):
        """ Initialize a QDockItem.

        Parameters
        ----------
        parent : QWidget, optional
            The parent of the dock item.

        """
        super(QDockItem, self).__init__(parent)
        layout = QDockItemLayout()
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSizeConstraint(QLayout.SetMinAndMaxSize)
        self.setLayout(layout)
        self.setTitleBarWidget(QDockTitleBar())

----------
        hidden : bool
            True if the title bar should be hidden, False otherwise.

        """
        raise NotImplementedError


class QDockTitleBar(QFrame, IDockTitleBar):
    """ A concrete implementation of IDockTitleBar.

    This class serves as the default title bar for a QDockItem.

    """
    #: A signal emitted when the maximize button is clicked.
    maximizeButtonClicked = Signal(bool)

    #: A signal emitted when the restore button is clicked.
    restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is clicked.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: A signal emitted when the pin button is toggled.
    pinButtonToggled = Signal(bool)

    #: A signal emitted when the title is edited by the user.
    titleEdited = Signal(unicode)

restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is clicked.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: A signal emitted when the pin button is toggled.
    pinButtonToggled = Signal(bool)

    #: A signal emitted when the title is edited by the user.
    titleEdited = Signal(str)

    #: A signal emitted when the empty area is left double clicked.
    leftDoubleClicked = Signal(QPoint)

    #: A signal emitted when the empty area is right clicked.
    rightClicked = Signal(QPoint)

    def __init__(self, parent=None):
        """ Initialize a QDockTitleBar.

        Parameters
        ----------
        parent : QWidget or None
            The parent of the title bar.

        """
        super(QDockTitleBar, self).__init__(parent)
        self._buttons = self.CloseButton | self.MaximizeButton | self.PinButton
        self._is_editable = False

}


class QCustomDockWidget(QDockWidget):
    """ A custom QDockWidget which adds some Enaml specific features.

    """
    #: A signal emitted when the dock widget is closed by the user.
    closed = Signal()

    #: A signal emitted when the dock widget is floated.
    floated = Signal()

    #: A signal emitted when the dock widget is docked. The payload
    #: will be the new dock area.
    docked = Signal(object)

    def __init__(self, parent=None):
        """ Initialize a QCustomDockWidget.

        """
        super(QCustomDockWidget, self).__init__(parent)
        self._title_bar_visible = True
        self._dock_area = Qt.LeftDockWidgetArea
        self.topLevelChanged.connect(self._onTopLevelChanged)

    #--------------------------------------------------------------------------
    # Private API
    #--------------------------------------------------------------------------
    def _onTopLevelChanged(self, top_level):
        """ The signal handler for the the 'topLevelChanged' signal.

class QDualSlider(QSlider):
    """ A Qt implementation of a dual slider.

    Dragging on the slider track will cause both the low and high values
    to move equally (i.e. the difference between them stays constant).

    TODO: Add support for tracking.

    """
    #: A signal emitted when the low value of the slider changes.
    lowValueChanged = Signal(int)

    #: A signal emitted when the high value of the slider changes.
    highValueChanged = Signal(int)

    #: Enums identifier the active slider thumb.
    BothThumbs = -1
    LowThumb = 0
    HighThumb = 1

    def __init__(self, parent=None):
        """ Initialize a QDualSlider.

        Parameters
        ----------
        parent : QWidget, optional
            The parent widget for the dual slider, or None.

        """
        super(QDualSlider, self).__init__(parent)

class QDockWindowButtons(QFrame):
    """ A custom QFrame which provides the buttons for a QDockWindow.

    """
    #: A signal emitted when the maximize button is clicked.
    maximizeButtonClicked = Signal(bool)

    #: A signal emitted when the restore button is clicked.
    restoreButtonClicked = Signal(bool)

    #: A signal emitted when the close button is closed.
    closeButtonClicked = Signal(bool)

    #: A signal emitted when the link button is toggled.
    linkButtonToggled = Signal(bool)

    #: Do not show any buttons in the widget.
    NoButtons = 0x0

    #: Show the maximize button in the widget.
    MaximizeButton = 0x1

    #: Show the restore button in the widget.
    RestoreButton = 0x2

    #: Show the close button in the widget.
    CloseButton = 0x4

    #: Show the link button in the widget.
    LinkButton = 0x8