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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 relation_path_for(from_name, to_name, identifier_type, identifier_key=None):
 """ Get a path relating a thing to another. """

    return "/{}/<{}:{}>/{}".format(
        name_for(from_name),
        identifier_type,
        identifier_key or "{}_id".format(name_for(from_name)),
        name_for(to_name),
    )