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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 vertices_per_edge(self):
 """Returns an Ex2 array of adjacencies between vertices, where each element in the array is a vertex index. Each edge is included only once. Edges that are not shared by 2 faces are not included."""

        import numpy as np
        return np.asarray([vertices_in_common(e[0], e[1]) for e in self.f[self.faces_per_edge]])