How to use the pyface.api.GUI function in pyface

def run_standalone(self):
        from mayavi.core.engine import Engine
        from mayavi.plugins.script import Script
        from pyface.api import ApplicationWindow, GUI

        self.setup_logger()
        if self.offscreen:
            engine = Engine(scene_factory=off_screen_viewer)
        else:
            engine = Engine()
        engine.start()

        self.exception_info = None
        self.script = Script(engine=engine)
        self.gui = g = GUI()
        self.app_window = a = ApplicationWindow()
        a.open()
        a.show(False)
        g.invoke_later(self.run)
        g.start_event_loop()
        if self.exception_info is not None:
            type, value, tb = self.exception_info
            if sys.version_info[0] > 2:
                raise type(value).with_traceback(tb)
            else:
                raise type(value)

def wrapper(*args, **kw):
        """Wrapper function to run given function inside the GUI event
        loop.
        """
        global _gui, _stop_show
        tk = ETSConfig.toolkit

        if is_ui_running():
            # In this case we should not pop up the UI since we likely
            # don't want to stop the mainloop.
            return func(*args, **kw)
        else:
            g = GUI()
            if tk == 'wx':
                # Create a dummy app so invoke later works on wx.
                a = ApplicationWindow(size=(1, 1))
                GUI.invoke_later(lambda: a.close())
                a.open()

            GUI.invoke_later(func, *args, **kw)
            _gui = g
            if stop:
                # Pop up the UI to stop the mainloop.
                _stop_show = StopShow()
            g.start_event_loop()

def draw(self):
        try:
        #if self.figure.canvas is not None:
            GUI.invoke_later(self.figure.canvas.draw)
        except:
            pass

def _loaded_changed(self, value):
        if value:
            n = self.dname
            if ' [Active]' not in n:
                self.dname = "%s [Loaded]" % n
                
            if not self.window is None:
                #from pyface.timer.api import do_later
                from pyface.api import GUI
                GUI.invoke_later(self.window.status_bar_manager.set, message = '')
            
        else:
            self.dname = self.dname.replace(' [Loaded]', '')

# ------------------------------------------------------------------------

    # Trait event handlers -------------------------------------------------

    def _on_tree_anytrait_changed(self, tree, trait_name, old, new):
        """ Called when any trait on the tree has changed. """

        print("trait", trait_name, "value", new)

        return


# Application entry point.
if __name__ == "__main__":
    # Create the GUI (this does NOT start the GUI event loop).
    gui = GUI()

    # Create and open the main window.
    window = MainWindow()
    window.open()

    # Start the GUI event loop.
    gui.start_event_loop()

def __call__(self, fname):
        """ Pops up the dialogs required for the import of the
            CSV to happen.
        """
        self.csv_loader = CSVLoader(filename=fname)
        self.csv_loader.guess_defaults()
        controller = CallbackCSVLoader(model=self.csv_loader,
                        callback=self.csv_loaded_callback)
        controller.edit_traits()

if __name__ == '__main__':
    from pyface.api import GUI
    source_factory = CSVSourceFactory()
    source_factory('mydata.csv')
    GUI().start_event_loop()

# mpl.rcParams['backend.qt4']='PySide'
from little_helpers import find_data_file, find_possible_sums, find_grid_connections
from bisect import bisect

# mpl.rc('font',**{'size': 22, 'family':'serif','serif':['Palatino']})
# mpl.rc('text', usetex=True)

mpl.rc('font', **{'size': 22})

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QT as NavigationToolbar
import matplotlib.pyplot as plt
import random

_gui = GUI()

bohr = 0.52917721
from abinit_handler import hartree

cov_radii = np.loadtxt(find_data_file('/data/cov_radii.dat')) / bohr

colors = {1: (0.8, 0.8, 0.8), 3: (0, 0.75, 0.75), 11: (0, 0.75, 0.75), 19: (0, 0.75, 0.75), 37: (0, 0.75, 0.75),
          5: (0.78, 0.329, 0.1176), 7: (0, 0, 1),
          6: (0.25, .25, .25), 8: (1, 0, 0), 9: (0, 1, 0), 17: (0, 1, 0), 35: (0, 1, 0), 16: (1, 1, 0),
          13: (0.68, 0.229, 0.1176), 31: (0.58, 0.15, 0.07), 15: (0, 0, 0.8), 33: (48 / 255, 139 / 255, 229 / 255)}

for i in range(21, 31):
    colors[i] = (0, 1, 1)

for i in range(39, 49):
    colors[i] = (0, 1, 1)

super(MainWindow, self).__init__(**traits)

        # Add a menu bar.
        self.menu_bar_manager = MenuBarManager(
            MenuManager(
                Action(name="E&xit", on_perform=self.close),
                Action(name="DoIt", on_perform=_main),
                name="&File",
            )
        )

        return


if __name__ == "__main__":
    gui = GUI()

    # Create and open the main window.
    window = MainWindow()
    window.open()

    _main()

    # Start the GUI event loop!
    gui.start_event_loop()

def _pos_llh_callback(self, data):
    # Updating an ArrayPlotData isn't thread safe (see chaco issue #9), so
    # actually perform the update in the UI thread.
    if self.running:
      GUI.invoke_later(self.pos_llh_callback, data)

ToolBarManager(Action(name="Baz"), orientation="vertical"),
            location="left",
        )

        self.add_tool_bar(
            ToolBarManager(Action(name="Buz"), orientation="vertical"),
            location="right",
        )

        return


# Application entry point.
if __name__ == "__main__":
    # Create the GUI (this does NOT start the GUI event loop).
    gui = GUI()

    # Create and open the main window.
    window = MainWindow()
    window.open()

    # Start the GUI event loop.
    gui.start_event_loop()