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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_dummy_class(klass, dependency):
 """ When a dependency of a class is not available, create a dummy class which throws ImportError when used. Args: klass (str):
 name of the class. dependency (str):
 name of the dependency. Returns: class: a class object """

    assert not building_rtfd()

    class _DummyMetaClass(type):
        # throw error on class attribute access
        def __getattr__(_, __):
            raise AttributeError("Cannot import '{}', therefore '{}' is not available".format(dependency, klass))

    @six.add_metaclass(_DummyMetaClass)
    class _Dummy(object):
        # throw error on constructor
        def __init__(self, *args, **kwargs):
            raise ImportError("Cannot import '{}', therefore '{}' is not available".format(dependency, klass))

    return _Dummy