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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 vectors(self, array):
 """ Sets the active vector """

        if array.ndim != 2:
            raise AssertionError('vector array must be a 2-dimensional array')
        elif array.shape[1] != 3:
            raise RuntimeError('vector array must be 3D')
        elif array.shape[0] != self.n_points:
            raise RuntimeError('Number of vectors be the same as the number of points')

        self.point_arrays[DEFAULT_VECTOR_KEY] = array
        self.active_vectors_name = DEFAULT_VECTOR_KEY