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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def tab_focus_request(self, reason):
 """ Handle a custom tab focus request. This method is called when focus is being set on the proxy as a result of a user-implemented focus traversal handler. This can be reimplemented by subclasses as needed. Parameters reason : Qt.FocusReason The reason value for the focus request. Returns ------- result : bool True if focus was set, False otherwise. """

        widget = self.focus_target()
        if not widget.focusPolicy & Qt.TabFocus:
            return False
        if not widget.isEnabled():
            return False
        if not widget.isVisibleTo(widget.window()):
            return False
        widget.setFocus(reason)
        return False