Pythonic sum of 2014 World Cup spendings

Copa2014.py

# coding: utf-8
from urllib.request import urlopen
from xml.etree import ElementTree


class Budget(object):
    '''2014 World Cup budget parser.'''

    def __init__(self, data_url):
        '''Parses XML from data_url.'''
        with urlopen(data_url) as response:
            self.tree = ElementTree.parse(response)

    def __iter__(self):
        '''Iterate over spending lines from the budget.'''
        xpath = './/copa:empreendimento'
        namespaces = {'copa': 'http://www.portaltransparencia.gov.br/copa2014'}
        for element in self.tree.iterfind(xpath, namespaces=namespaces):
            yield Spending(element)


class Spending(object):
    '''2014 World Cup spending line.'''

    def __init__(self, element):
        self.element = element

    @property
    def value(self):
        '''Get the spending value, if any.'''
        value = self.element.find('./valorTotalPrevisto')
        return None if value is None else float(value.text)

    @property
    def started(self):
        '''Check whether spending has started.'''
        return self.element.find('./andamento/id').text != '1'


if __name__ == '__main__':
    # setup locale for pretty printing the spending.
    import locale
    locale.setlocale(locale.LC_ALL, 'pt_BR.UTF-8')

    budget = Budget('http://www.portaltransparencia.gov.br/copa2014/api/rest/empreendimento')
    total_spending = sum(spending.value for spending in budget 
                         if (spending.value is not None) and spending.started)

    print(locale.currency(total_spending, grouping=True))

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