code: def _centroids(self, verts):
          r'''
          Function to calculate the centroid as the mean of a set of vertices.
          Used for pore and throat.
          '''
          value = sp.zeros([len(verts), 3])
          for i, i_verts in enumerate(verts):
              value[i] = np.mean(i_verts, axis=0)
          return valuf _centroids(self, verts):
          r'''
          Function to calculate the centroid as the mean of a set of vertices.
          Used for pore and throat.
          '''
          value = sp.zeros([len(verts), 3])
          for i, i_verts in enumerate(verts):
              value[i] = np.mean(i_verts, axis=0)
          return value
docs: r'''
          Function to calculate the centroid as the mean of a set of vertices.
          Used for pore and throat.