code: def _add_not_exposed(
          analysis_row,
          enable_rounding,
          is_population,
          exposure_unit,
          coefficient):
      
      # We add the not exposed class at the end.
      not_exposed_field = (
          hazard_count_field['field_name'] % not_exposed_class['key'])
      try:
          value = analysis_row[not_exposed_field]
      except KeyError:
          # The field might not exist if there is not feature not exposed.
          value = 0
      value = format_number(value, enable_rounding, is_population, coefficient)
      label = _format_label(
          hazard_class=not_exposed_class['name'],
          value=value,
          exposure_unit=exposure_unit)
  
      return not_exposed_class['color'], label
docs: Helper to add the `not exposed` item to the legend.
  
      :param analysis_row: The analysis row as a list.
      :type analysis_row: list
  
      :param enable_rounding: If we need to do a rounding.
      :type enable_rounding: bool
  
      :param is_population: Flag if the number is population. It needs to be
          used with enable_rounding.
      :type is_population: bool
  
      :param exposure_unit: The exposure unit.
      :type exposure_unit: safe.definitions.units
  
      :param coefficient: Divide the result after the rounding.
      :type coefficient:float
  
      :return: A tuple with the color and the formatted label.
      :rtype: tuple