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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_starting_ratio(self, ratio):
 """ Set the starting conversion ratio for the next `read` call. """

        from samplerate.lowlevel import src_set_ratio
        if self._state is None:
            self._create()
        src_set_ratio(self._state, ratio)
        self.ratio = ratio