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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 ref_coords(self):
        '''Returns a pyfastaq.intervals.Interval object of the start and end coordinates in the reference sequence'''
        return pyfastaq.intervals.Interval(min(self.ref_start, self.ref_end), max(self.ref_start, self.ref_end))