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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 convert_value(value, source_currency, target_currency):
 """Converts the price of a currency to another one using exchange rates :param price: the price value :param type: decimal :param source_currency: source ISO-4217 currency code :param type: str :param target_currency: target ISO-4217 currency code :param type: str :returns: converted price instance :rtype: ``Price`` """

    # If price currency and target currency is same
    # return given currency as is
    if source_currency == target_currency:
        return value

    rate = get_rate(source_currency, target_currency)

    return value * rate