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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 to_palabos(im, filename, solid=0):
 r""" Converts an ND-array image to a text file that Palabos can read in as a geometry for Lattice Boltzmann simulations. Uses a Euclidean distance transform to identify solid voxels neighboring fluid voxels and labels them as the interface. Parameters im : ND-array The image of the porous material filename : string Path to output file solid : int The value of the solid voxels in the image used to convert image to binary with all other voxels assumed to be fluid. Notes ----- File produced contains 3 values: 2 = Solid, 1 = Interface, 0 = Pore Palabos will run the simulation applying the specified pressure drop from x = 0 to x = -1. """

    # Create binary image for fluid and solid phases
    bin_im = im == solid
    # Transform to integer for distance transform
    bin_im = bin_im.astype(int)
    # Distance Transform computes Euclidean distance in lattice units to
    # Nearest fluid for every solid voxel
    dt = nd.distance_transform_edt(bin_im)
    dt[dt > np.sqrt(2)] = 2
    dt[(dt > 0)*(dt <= np.sqrt(2))] = 1
    dt = dt.astype(int)
    # Write out data
    with open(filename, 'w') as f:
        out_data = dt.flatten().tolist()
        f.write('\n'.join(map(repr, out_data)))