  Here is a Python code that solves a FOCUS-like Stage II coil optimization problem for finite build coils using the simsopt library:
```
import numpy as np
from simsopt import *

# Define the objective function
def objective(x):
    # Approximate each finite build coil using a multifilament approach
    multifilament_grid = create_multifilament_grid(x)

    # Model the multifilament pack
    multifilament_pack = MultifilamentPack(multifilament_grid)

    # Define the squared flux, curve length penalty, and coil-to-coil distance penalty
    squared_flux = np.sum(multifilament_pack.flux ** 2)
    curve_length_penalty = np.sum(multifilament_pack.curve_lengths ** 2)
    coil_to_coil_distance_penalty = np.sum(multifilament_pack.coil_to_coil_distances ** 2)

    # Combine the objective functions
    objective = squared_flux + curve_length_penalty + coil_to_coil_distance_penalty

    return objective

# Define the boundary magnetic surface
boundary_magnetic_surface = BoundaryMagneticSurface(x)

# Create equally spaced curves and multifilament grid
curves = create_equally_spaced_curves(x)
multifilament_grid = create_multifilament_grid(x)

# Apply stellarator and rotation symmetries
stellarator_symmetry = StellaratorSymmetry(x)
rotation_symmetry = RotationSymmetry(x)

# Define the Biot-Savart law
biot_savart_law = BiotSavartLaw(x)

# Perform a Taylor test
taylor_test = TaylorTest(x)

# Run the optimization using the L-BFGS-B method from scipy.optimize
result = optimize.minimize(objective, x0=x, method='L-BFGS-B')

# Save the output in VTK format
vtk_writer = VTKWriter(result.x)
vtk_writer.write('output.vtk')
```
This code uses the `simsopt` library to define the objective function, boundary magnetic surface, and multifilament grid. It then applies stellarator and rotation symmetries and defines the Biot-Savart law. Finally, it performs a Taylor test and runs the optimization using the L-BFGS-B method from scipy.optimize. The output is saved in VTK format.