<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _set_survey_scenario(self, survey_scenario):
 """ Set survey scenario :param survey_scenario: the survey scenario """

        self.survey_scenario = survey_scenario
        # TODO deal with baseline if reform is present
        if survey_scenario.simulation is None:
            survey_scenario.simulation = survey_scenario.new_simulation()
        period = self.period
        self.filter_by = filter_by = survey_scenario.calculate_variable(
            variable = self.filter_by_name, period = period)
        # TODO: shoud not be france specific
        self.weight_name = weight_name = self.survey_scenario.weight_column_name_by_entity['menage']
        self.initial_weight_name = weight_name + "_ini"
        self.initial_weight = initial_weight = survey_scenario.calculate_variable(
            variable = weight_name, period = period)
        self.initial_total_population = sum(initial_weight * filter_by)
        self.weight = survey_scenario.calculate_variable(variable = weight_name, period = period)