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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_outliers_percentage(pronac):
 """ Returns the percentage of items of the project that are outliers. """

    items = (
        data.items_with_price
        .groupby(['PRONAC'])
        .get_group(pronac)
    )

    df = data.aggregated_relevant_items

    outlier_items = {}
    url_prefix = '/prestacao-contas/analisar/comprovante'

    for _, item in items.iterrows():
        item_id = item['idPlanilhaItens']
        price = item['VlUnitarioAprovado']
        segment_id = item['idSegmento']
        item_name = item['Item']

        if is_outlier(df, item_id, segment_id, price):
            outlier_items[item_id] = {
                'name': item_name,
                'salic_url': get_salic_url(item, url_prefix),
                'has_receipt': has_receipt(item)
            }

    total_items = items.shape[0]
    outliers_amount = len(outlier_items)

    percentage = outliers_amount / total_items

    return {
        'items': outlier_items,
        'valor': outliers_amount,
        'total_items': total_items,
        'percentage': percentage,
        'is_outlier': outliers_amount > 0,
    }