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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 __focus(self, item):
 """Called when focus item has changed"""

        cols = self.__get_display_columns()
        for col in cols:
            self.__event_info =(col,item)
            self.event_generate('<<TreeviewInplaceEdit>>')
            if col in self._inplace_widgets:
                w = self._inplace_widgets[col]
                w.bind('<Key-Tab>',
                    lambda e: w.tk_focusNext().focus_set())
                w.bind('<Shift-Key-Tab>',
                    lambda e: w.tk_focusPrev().focus_set())