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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_window_function(name, doc=''):
 """ Create a window function by name """

    def _():
        sc = SparkContext._active_spark_context
        jc = getattr(sc._jvm.functions, name)()
        return Column(jc)
    _.__name__ = name
    _.__doc__ = 'Window function: ' + doc
    return _