Refiniment error

I am trying to make marker based refinement of the mesh. It is 2D task, using MixedElement and RectangleMesh as coarse mesh. But the following error occurs “TypeError: expected the geometry argument to be of length 2” in phi_n_fine_value = phi_n_fine§.

The source code is
L = 150 # domain size
W_0 = 1.0 # interface thickness
N_el = np.int64(L * n_delta / W_0) # number of elements in calculation
n_delta = 0.25 # number of elements per diffusive width
mesh_coarse = RectangleMesh(Point(0,0),Point(L,L),N_el,N_el) # mesh definition
P3 = FiniteElement(‘P’, triangle, 3) # Langrange Element
element = MixedElement([P3,P3,P3]) # Mixed element
V_coarse = FunctionSpace(mesh_coarse,element)

class In_Expr(UserExpression): # class for initial conditions

def eval(self, values, x):
    values[0] = -delta # initial conditions for undercooling variable
    values[1] = -np.tanh(0.3*W_0*((x[0]*x[0]+x[1]*x[1]) ** 0.5 - r)) # initial conditions for phase state variable
    values[2] = 0

def value_shape(self):
    return(3,)

print(‘Interpolation on coarse mesh:’)
sol_n_coarse = interpolate(In_Expr(),V_coarse) # function for storage of solution on (n-1) step

Mesh adaptation

print(‘Mesh adaptation’)
mesh_fine = mesh_coarse # new adapted mesh
sol_n_fine = sol_n_coarse # refined solution
for cycle in range(refinement_cycles):
refine_subdomain = MeshFunction(‘bool’,mesh_fine,2)
refine_subdomain.set_all(False)
for cell in cells(mesh_fine):
p = cell.midpoint()
u_n_fine, phi_n_fine, mu_n_fine = split(sol_n_fine)
phi_n_fine_value = phi_n_fine§