def METHOD_NAME(self):
    exp = 293.3 * 293.3 * 30  # cubicfeet = 73 078.6084 cubic meter
    exp *= (12*0.0254)**3  # cubic feet to cubic meter
    grid  = self.spe3.grid()
    for i in range(grid.nx):
        for j in range(grid.ny):
            for k in range(grid.nz):
                g_idx = grid.globalIndex(i,j,k)
                if k == 0:
                    self.assertClose(exp, grid.getCellVolume(g_idx))
                self.assertEqual(grid.getCellVolume(g_idx), grid.getCellVolume(i, j, k))
    celVol1 = grid.getCellVolume()
    self.assertTrue(isinstance(celVol1, np.ndarray))
    self.assertEqual(celVol1.dtype, "float64")
    self.assertEqual(len(celVol1), grid.nx*grid.ny*grid.nz)
    mask = [0] * (grid.nx*grid.ny*grid.nz)
    for ind in [0,10,11,12,15]:
        mask[ind]=1
    self.assertEqual(len(mask), grid.nx*grid.ny*grid.nz)
    self.assertEqual(sum(mask), 5)
    celVol2 = grid.getCellVolume(mask)
    self.assertEqual(len(celVol2), grid.nx*grid.ny*grid.nz)
    self.assertClose(exp, sum(celVol2)/5.0)