<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_editor(self, editor):
 """ Sets the current editor. The widget display the structure of that editor. :param editor: CodeEdit """

        try:
            self._editor.cursorPositionChanged.disconnect(self.sync)
        except (AttributeError, TypeError, RuntimeError, ReferenceError):
            pass
        try:
            self._outline_mode.document_changed.disconnect(
                self._on_changed)
        except (AttributeError, TypeError, RuntimeError, ReferenceError):
            pass
        try:
            self._folding_panel.trigger_state_changed.disconnect(
                self._on_block_state_changed)
        except (AttributeError, TypeError, RuntimeError, ReferenceError):
            pass
        if editor:
            self._editor = weakref.proxy(editor)
        else:
            self._editor = None

        if editor is not None:
            editor.cursorPositionChanged.connect(self.sync)
            try:
                self._folding_panel = weakref.proxy(
                    editor.panels.get(FoldingPanel))
            except KeyError:
                pass
            else:
                self._folding_panel.trigger_state_changed.connect(
                    self._on_block_state_changed)
            try:
                analyser = editor.modes.get(OutlineMode)
            except KeyError:
                self._outline_mode = None
            else:
                self._outline_mode = weakref.proxy(analyser)
                analyser.document_changed.connect(self._on_changed)
        self._on_changed()