'Calculate bom totals'

def calculate_cost(self):

    self.calculate_op_cost()
    self.calculate_rm_cost()
    self.calculate_sm_cost()
    self.total_cost = ((self.operating_cost + self.raw_material_cost) - self.scrap_material_cost)
    self.base_total_cost = ((self.base_operating_cost + self.base_raw_material_cost) - self.base_scrap_material_cost)
