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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 find_country(session, code):
 """Find a country. Find a country by its ISO-3166 `code` (i.e ES for Spain, US for United States of America) using the given `session. When the country does not exist the function will return `None`. :param session: database session :param code: ISO-3166 code of the country to find :return: a country object; `None` when the country does not exist """

    country = session.query(Country).\
        filter(Country.code == code).first()

    return country