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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 rmsd_eval(cls, specification, sequences, parameters, reference_ampal, **kwargs):
 """Creates optimizer with default build and RMSD eval. Notes ----- Any keyword arguments will be propagated down to BaseOptimizer. RMSD eval is restricted to a single core only, due to restrictions on closure pickling. Parameters specification : ampal.assembly.specification Any assembly level specification. sequences : [str] A list of sequences, one for each polymer. parameters : [base_ev_opt.Parameter] A list of `Parameter` objects in the same order as the function signature expects. reference_ampal : ampal.Assembly The target structure of the optimisation. """

        eval_fn = make_rmsd_eval(reference_ampal)
        instance = cls(specification,
                       sequences,
                       parameters,
                       build_fn=default_build,
                       eval_fn=eval_fn,
                       mp_disabled=True,
                       **kwargs)
        return instance