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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 register_subsearcher(name, subsearcher_cls):
 """ register a subsearcher, the `name` is a key used for searching subsearchers. if the subsearcher named `name` already exists, then it's will overrite the old subsearcher. """

    if not issubclass(subsearcher_cls, BaseSubSearcher):
        raise ValueError(
            '{} is not a subclass of BaseSubSearcher'.format(subsearcher_cls))
    registered_subsearchers[name] = subsearcher_cls