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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 set_calg_cb(self, w, index):
 """This callback is invoked when the user selects a new color hashing algorithm from the preferences pane."""

        #index = w.get_index()
        name = self.calg_names[index]
        self.t_.set(color_algorithm=name)