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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 get_reader_classes(parent=Reader):
 """Get all childless the descendants of a parent class, recursively."""

    children = parent.__subclasses__()
    descendants = children[:]
    for child in children:
        grandchildren = get_reader_classes(child)
        if grandchildren:
            descendants.remove(child)
            descendants.extend(grandchildren)
    return descendants