def load_country_tz(filename, winter=True):
    """
    Load the list of country timzones from a csv file

    Parameters
    ----------
    filename: String
        Path to the csv file containing the timezone information
    winter: bool (defaut to True)
        Wether the winter time or the summertime is considered

    Returns
    -------
    dict(str : int)
        A dictionary mapping the iso3 country codes to the corresponding
        timezone (hours offset from UTC)
    """
    ctz = dict()
    with open(filename) as f:
        for line in f:
            words = line.split(";")
            if len(words[0].strip()) == 3:
                ctz[words[0].strip()] = int(words[2])
                if not winter:
                    ctz[words[0].strip()] += int(words[3])
    return ctz