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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 relevant_items(df):
 """ Dataframe with items used by cultural projects, filtered by date and price. """

    start_date = datetime(2013, 1, 1)

    df['DataProjeto'] = pd.to_datetime(df['DataProjeto'])

    # get only projects newer than start_date
    # and items with price > 0
    df = df[df.DataProjeto >= start_date]
    df = df[df.VlUnitarioAprovado > 0.0]

    return df