How to use the pudb.ui_tools.SignalWrap function in pudb

self.debugger = dbg

        from urwid import AttrMap

        from pudb.ui_tools import SearchController
        self.search_controller = SearchController(self)

        self.last_module_filter = ""

        # {{{ build ui

        # {{{ left/source column

        self.source = urwid.SimpleListWalker([])
        self.source_list = urwid.ListBox(self.source)
        self.source_sigwrap = SignalWrap(self.source_list)
        self.source_attr = urwid.AttrMap(self.source_sigwrap, "source")
        self.source_hscroll_start = 0

        self.cmdline_history = []
        self.cmdline_history_position = -1

        self.cmdline_contents = urwid.SimpleFocusListWalker([])
        self.cmdline_list = urwid.ListBox(self.cmdline_contents)
        self.cmdline_edit = urwid.Edit([
            ("command line prompt", ">>> ")
            ])
        cmdline_edit_attr = urwid.AttrMap(self.cmdline_edit, "command line edit")
        self.cmdline_edit_sigwrap = SignalWrap(
                cmdline_edit_attr, is_preemptive=True)

        def clear_cmdline_history(btn):

def clear_cmdline_history(btn):
            del self.cmdline_contents[:]

        self.cmdline_edit_bar = urwid.Columns([
                self.cmdline_edit_sigwrap,
                ("fixed", 10, AttrMap(
                    urwid.Button("Clear", clear_cmdline_history),
                    "command line clear button", "command line focused button"))
                ])

        self.cmdline_pile = urwid.Pile([
            ("flow", urwid.Text("Command line: [Ctrl-X]")),
            ("weight", 1, urwid.AttrMap(self.cmdline_list, "command line output")),
            ("flow", self.cmdline_edit_bar),
            ])
        self.cmdline_sigwrap = SignalWrap(
                urwid.AttrMap(self.cmdline_pile, None, "focused sidebar")
                )
        self.cmdline_on = not CONFIG["hide_cmdline_win"]
        self.cmdline_weight = 1
        self.lhs_col = urwid.Pile([
            ("weight", 5, self.source_attr),
            ("weight", self.cmdline_weight if self.cmdline_on else 0,
                self.cmdline_sigwrap),
            ])

        # }}}

        # {{{ right column

        self.locals = urwid.SimpleListWalker([])
        self.var_list = SignalWrap(

def dialog(self, content, buttons_and_results,
            title=None, bind_enter_esc=True, focus_buttons=False,
            extra_bindings=[]):
        class ResultSetter:
            def __init__(subself, res):
                subself.res = res

            def __call__(subself, btn):
                self.quit_event_loop = [subself.res]

        Attr = urwid.AttrMap

        if bind_enter_esc:
            content = SignalWrap(content)
            def enter(w, size, key): self.quit_event_loop = [True]
            def esc(w, *args): self.quit_event_loop = [False]
            content.listen("enter", enter)
            content.listen("esc", esc)
            content.listen_mouse_event("mouse press", 3, esc)

        button_widgets = []
        for btn_descr in buttons_and_results:
            if btn_descr is None:
                button_widgets.append(urwid.Text(""))
            else:
                btn_text, btn_result = btn_descr
                button_widgets.append(
                        Attr(urwid.Button(btn_text, ResultSetter(btn_result)),
                            "button", "focused button"))

Attr = urwid.AttrMap

        self.search_box = None
        self.last_module_filter = ""

        self.source = urwid.SimpleListWalker([])
        self.source_list = urwid.ListBox(self.source)
        self.source_sigwrap = SignalWrap(self.source_list)
        self.source_hscroll_start = 0

        self.lhs_col = urwid.Pile([
            ("weight", 1, urwid.AttrMap(self.source_sigwrap, "source"))
            ])

        self.locals = urwid.SimpleListWalker([])
        self.var_list = SignalWrap(
                urwid.ListBox(self.locals))

        self.stack_walker = urwid.SimpleListWalker([])
        self.stack_list = SignalWrap(
                urwid.ListBox(self.stack_walker))

        self.bp_walker = urwid.SimpleListWalker([])
        self.bp_list = SignalWrap(
                urwid.ListBox(self.bp_walker))

        self.rhs_col = urwid.Pile([
            ("weight", float(CONFIG["variables_weight"]), Attr(urwid.Pile([
                ("flow", urwid.Text(make_hotkey_markup("_Variables:"))),
                Attr(self.var_list, "variables"),
                ]), None, "focused sidebar"),),
            ("weight", float(CONFIG["stack_weight"]), Attr(urwid.Pile([

def dialog(self, content, buttons_and_results,
            title=None, bind_enter_esc=True, focus_buttons=False,
            extra_bindings=[]):
        class ResultSetter:
            def __init__(subself, res):  # noqa
                subself.res = res

            def __call__(subself, btn):  # noqa
                self.quit_event_loop = [subself.res]

        Attr = urwid.AttrMap  # noqa

        if bind_enter_esc:
            content = SignalWrap(content)

            def enter(w, size, key):
                self.quit_event_loop = [True]

            def esc(w, size, key):
                self.quit_event_loop = [False]

            content.listen("enter", enter)
            content.listen("esc", esc)

        button_widgets = []
        for btn_descr in buttons_and_results:
            if btn_descr is None:
                button_widgets.append(urwid.Text(""))
            else:
                btn_text, btn_result = btn_descr

self.source = urwid.SimpleListWalker([])
        self.source_list = urwid.ListBox(self.source)
        self.source_sigwrap = SignalWrap(self.source_list)
        self.source_hscroll_start = 0

        self.lhs_col = urwid.Pile([
            ("weight", 1, urwid.AttrMap(self.source_sigwrap, "source"))
            ])

        self.locals = urwid.SimpleListWalker([])
        self.var_list = SignalWrap(
                urwid.ListBox(self.locals))

        self.stack_walker = urwid.SimpleListWalker([])
        self.stack_list = SignalWrap(
                urwid.ListBox(self.stack_walker))

        self.bp_walker = urwid.SimpleListWalker([])
        self.bp_list = SignalWrap(
                urwid.ListBox(self.bp_walker))

        self.rhs_col = urwid.Pile([
            ("weight", float(CONFIG["variables_weight"]), Attr(urwid.Pile([
                ("flow", urwid.Text(make_hotkey_markup("_Variables:"))),
                Attr(self.var_list, "variables"),
                ]), None, "focused sidebar"),),
            ("weight", float(CONFIG["stack_weight"]), Attr(urwid.Pile([
                ("flow", urwid.Text(make_hotkey_markup("_Stack:"))),
                Attr(self.stack_list, "stack"),
                ]), None, "focused sidebar"),),
            ("weight", float(CONFIG["breakpoints_weight"]), Attr(urwid.Pile([

content,
            ("fixed", 15, urwid.ListBox(button_widgets)),
            ], dividechars=1)

        if focus_buttons:
            w.set_focus_column(1)

        if title is not None:
            w = urwid.Pile([
                ("flow", urwid.AttrMap(
                    urwid.Text(title, align="center"),
                    "dialog title")),
                ("fixed", 1, urwid.SolidFill()),
                w])

        w = SignalWrap(w)
        for key, binding in extra_bindings:
            w.listen(key, binding)

        w = urwid.LineBox(w)

        w = urwid.Overlay(w, self.top,
                align="center",
                valign="middle",
                width=('relative', 75),
                height=('relative', 75),
                )
        w = Attr(w, "background")

        return self.event_loop(w)[0]