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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 compute_rotsym(molecule, graph, threshold=1e-3*angstrom):
 """Compute the rotational symmetry number Arguments: | ``molecule`` -- The molecule | ``graph`` -- The corresponding bond graph Optional argument: | ``threshold`` -- only when a rotation results in an rmsd below the given threshold, the rotation is considered to transform the molecule onto itself. """

    result = 0
    for match in graph.symmetries:
        permutation = list(j for i,j in sorted(match.forward.items()))
        new_coordinates = molecule.coordinates[permutation]
        rmsd = fit_rmsd(molecule.coordinates, new_coordinates)[2]
        if rmsd < threshold:
            result += 1
    return result