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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 range(self):
 """Get the range from the leftmost exon to the rightmost :return: total range :rtype: GenomicRange """

    return GenomicRange(self._rngs[0].chr,self._rngs[0].start,self._rngs[-1].end)