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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 create_registry(interface):
 """ Create a new registry for an extensible interface. Parameters interface : type The abstract data type for which to create a registry, which will manage registration of factories for this type. Returns ------- interface : type The data type specified/decorated, unaltered. """

    if interface in custom_types:
        raise ValueError('there is already a Registry instance '
                         'for the specified type')
    custom_types[interface] = Registry(interface)
    return interface