code: def post_processor_population_displacement_function(
          hazard=None, classification=None, hazard_class=None, population=None):
      
      _ = population  # NOQA
  
      return get_displacement_rate(hazard, classification, hazard_class)
docs: Private function used in the displacement postprocessor.
  
      :param hazard: The hazard to use.
      :type hazard: str
  
      :param classification: The hazard classification to use.
      :type classification: str
  
      :param hazard_class: The hazard class of the feature.
      :type hazard_class: str
  
      :param population: We don't use this value here. It's only used for
          condition for the postprocessor to run.
      :type population: float, int
  
      :return: The displacement ratio for a given hazard class.
      :rtype: float