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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 verts_in_common(self, segments):
 """ returns array of all vertex indices common to each segment in segments"""

        verts_by_segm = self.verts_by_segm
        return sorted(reduce(lambda s0, s1: s0.intersection(s1),
                             [set(verts_by_segm[segm]) for segm in segments]))