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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 _set_model_metadata(mlmodel, model_class, metadata, version=None):
 """ Sets user-defined metadata, making sure information all models should have is also available """

    info = _get_model_metadata(model_class, metadata, version)
    mlmodel.user_defined_metadata.update(info)