def METHOD_NAME(self, first_element, value):
    # StatisticValues is a struct type so we are parsing
    # a csv keyval list into a dict.
    statistics = {}
    for pair in split_on_commas(value):
        key, value = pair.split('=')
        # There are four supported values: Maximum, Minimum, SampleCount,
        # and Sum.  All of them are documented as a type double so we can
        # convert these to a decimal value to preserve precision.
        statistics[key] = decimal.Decimal(value)
    first_element['StatisticValues'] = statistics