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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 to_prettytable(df):
 """Convert DataFrame into ``PrettyTable``. """

    pt = PrettyTable()
    pt.field_names = df.columns
    for tp in zip(*(l for col, l in df.iteritems())):
        pt.add_row(tp)
    return pt