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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 _start_selecting(self, event):
 """Comienza con el proceso de seleccion."""

        self._selecting = True
        canvas = self._canvas
        x = canvas.canvasx(event.x)
        y = canvas.canvasy(event.y)
        self._sstart = (x, y)
        if not self._sobject:
            self._sobject = canvas.create_rectangle(
                self._sstart[0], self._sstart[1], x, y,
                dash=(3,5), outline='#0000ff'
            )
        canvas.itemconfigure(self._sobject, state=tk.NORMAL)