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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 lpad(col, len, pad):
 """ Left-pad the string column to width `len` with `pad`. [Row(s=u'##abcd')] """

    sc = SparkContext._active_spark_context
    return Column(sc._jvm.functions.lpad(_to_java_column(col), len, pad))