How to use the asciimatics.screen.Screen.ctrl function in asciimatics

effect.update(3)
        self.assert_canvas_equals(
            canvas,
            "++------------------------------------++\n" +
            "||Item 2                              ||\n" +
            "||------------------------------------|O\n" +
            "||Item 1                              ||\n" +
            "||Item 2                              ||\n" +
            "||Item 3                              ||\n" +
            "|+------------------------------------+|\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "+--------------------------------------+\n")

        # Check Enter works as expected
        self.process_keys(scene, [Screen.ctrl("m")])
        for effect in scene.effects:
            effect.update(4)
        self.assert_canvas_equals(
            canvas,
            "+--------------------------------------+\n" +
            "|[Item 2                              ]|\n" +
            "|                                      O\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "+--------------------------------------+\n")

def test_ctrl(self):
        """
        Check that ctrl returns the right values.
        """
        # Check standard alphabetical range
        for i, char in enumerate(range(ord('@'), ord('Z'))):
            self.assertEqual(Screen.ctrl(char), i)
            self.assertEqual(Screen.ctrl(chr(char)), i)
            self.assertEqual(Screen.ctrl(chr(char).lower()), i)

        # Check last few options - which mostly aren't actually returned in
        # Linux and so probably only of limited value, but what the heck!
        for i, char in enumerate(["[", "\\", "]", "^", "_"]):
            self.assertEqual(Screen.ctrl(char), i + 27)

        # Check other things return None - pick boundaries for checks.
        for char in ["?", "`", "\x7f"]:
            self.assertIsNone(Screen.ctrl(char))

Check that ctrl returns the right values.
        """
        # Check standard alphabetical range
        for i, char in enumerate(range(ord('@'), ord('Z'))):
            self.assertEqual(Screen.ctrl(char), i)
            self.assertEqual(Screen.ctrl(chr(char)), i)
            self.assertEqual(Screen.ctrl(chr(char).lower()), i)

        # Check last few options - which mostly aren't actually returned in
        # Linux and so probably only of limited value, but what the heck!
        for i, char in enumerate(["[", "\\", "]", "^", "_"]):
            self.assertEqual(Screen.ctrl(char), i + 27)

        # Check other things return None - pick boundaries for checks.
        for char in ["?", "`", "\x7f"]:
            self.assertIsNone(Screen.ctrl(char))

self.assert_canvas_equals(
            canvas,
            "+-----|30 Jan 2016|--------------------+\n" +
            "|Date:|31/Feb/2017|                    |\n" +
            "|Time:|   Mar 2018|                    O\n" +
            "|     +-----------+                    |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "+--------------------------------------+\n")

        # Check that a valid date updates the value - wait one second to allow search to reset.
        sleep(1)
        self.process_keys(scene, ["15", "Jun", Screen.ctrl("m")], separator=Screen.KEY_TAB)
        self.assertTrue(form.changed)
        for effect in scene.effects:
            effect.update(2)
        self.assert_canvas_equals(
            canvas,
            "+--------------------------------------+\n" +
            "|Date: 15/Jun/2017                     |\n" +
            "|Time: 12:00:59                        O\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "|                                      |\n" +
            "+--------------------------------------+\n")
        self.assertEquals(form.date_widget.value, date(2017, 6, 15))

form.update(1)
        self.assert_canvas_equals(
            canvas,
            "/A Directory          Size Last modified\n" +
            "|-+ ..                                  \n" +
            "|-+ A Directory         9K    1970-01-01\n" +
            "|-- A File              9K    1970-01-01\n" +
            "|-- A Lnk -> A Tgt      9K    1970-01-01\n" +
            "|-- oööÖ.txt            9K    1970-01-01\n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n")

        # Check that enter key handles correctly on files.
        self.process_keys(form, [Screen.KEY_DOWN, Screen.KEY_DOWN, Screen.ctrl("m")])
        self.assertEqual(form.highlighted, "/A Directory/A File")
        self.assertEqual(form.selected, "/A Directory/A File")

form.update(0)
        self.assert_canvas_equals(
            canvas,
            "/                     Size Last modified\n" +
            "|-+ A Directory         9K    1970-01-01\n" +
            "|-- hello.bmp           9K    1970-01-01\n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n" +
            "                                        \n")

        # Check that enter key handles correctly on files.
        self.process_keys(form, [Screen.KEY_DOWN, Screen.KEY_DOWN, Screen.ctrl("m")])
        self.assertEqual(form.highlighted, "/hello.bmp")
        self.assertEqual(form.selected, "/hello.bmp")

def process_event(self, event):
            if isinstance(event, asciimatics.event.KeyboardEvent):
                # key handling for this: Ctrl-C, q/Q to quit, r refresh
                if event.key_code in [
                        ord('q'),
                        ord('Q'),
                        asciimatics.screen.Screen.KEY_ESCAPE,
                        asciimatics.screen.Screen.ctrl("c")
                ]:
                    raise asciimatics.exceptions.StopApplication("User quit")
                elif event.key_code in [ ord("r"), ord("R") ]:
                    pass
                self.last_frame = 0	# force a refresh
            return asciimatics.widgets.Frame.process_event(self, event)

def process_event(self, event):
        """User input for the main map view."""
        if isinstance(event, KeyboardEvent):
            if event.key_code in [Screen.ctrl("m"), Screen.ctrl("j")]:
                self._scene.add_effect(
                    EnterLocation(
                        self._screen, self._longitude, self._latitude, self._on_new_location))
            elif event.key_code in [ord('q'), ord('Q'), Screen.ctrl("c")]:
                raise StopApplication("User quit")
            elif event.key_code in [ord('t'), ord('T')]:
                self._satellite = not self._satellite
                if self._satellite:
                    self._size = _START_SIZE
            elif event.key_code == ord("?"):
                self._scene.add_effect(PopUpDialog(self._screen, _HELP, ["OK"]))
            elif event.key_code == ord("+") and self._zoom <= 20:
                if self._desired_zoom < 20:
                    self._desired_zoom += 1
            elif event.key_code == ord("-") and self._zoom >= 0:
                if self._desired_zoom > 0:

def process_event(self, event):
        """Summary

        Args:
            event (TYPE): Description

        Returns:
            TYPE: Description

        Raises:
            StopApplication: Description
        """
        # Do the key handling for this Frame.
        if isinstance(event, KeyboardEvent):
            if event.key_code in [ord('q'), ord('Q'), Screen.ctrl("c")]:
                raise StopApplication("User quit")

            # Force a refresh for improved responsiveness
            self._last_frame = 0

        # Now pass on to lower levels for normal handling of the event.
        return super(StatusFrame, self).process_event(event)

self._line = max(0, self._line - 1)
                self.value = self._options[self._line][1]
            elif len(self._options) > 0 and event.key_code == Screen.KEY_DOWN:
                # Move down one line in text - use value to trigger on_select.
                self._line = min(len(self._options) - 1, self._line + 1)
                self.value = self._options[self._line][1]
            elif len(self._options) > 0 and event.key_code == Screen.KEY_PAGE_UP:
                # Move up one page.
                self._line = max(0, self._line - self._h + (1 if self._titles else 0))
                self.value = self._options[self._line][1]
            elif len(self._options) > 0 and event.key_code == Screen.KEY_PAGE_DOWN:
                # Move down one page.
                self._line = min(
                    len(self._options) - 1, self._line + self._h - (1 if self._titles else 0))
                self.value = self._options[self._line][1]
            elif event.key_code in [Screen.ctrl("m"), Screen.ctrl("j")]:
                # Fire select callback.
                if self._on_select:
                    self._on_select()
            elif event.key_code > 0:
                # Treat any other normal press as a search
                now = datetime.now()
                if now - self._last_search >= timedelta(seconds=1):
                    self._search = ""
                self._search += chr(event.key_code)
                self._last_search = now

                # If we find a new match for the search string, update the list selection
                new_value = self._find_option(self._search)
                if new_value is not None:
                    self.value = new_value
            else: