code: def _fields_sort_by_indicators(fields):
      
      field_dict = {}
      field_positions_global = []
      for field in fields:
          field_dict.setdefault(field[1:3], []).append(field)
          field_positions_global.append(field[4])
  
      indicators = field_dict.keys()
      indicators.sort()
  
      field_list = []
      for indicator in indicators:
          for field in field_dict[indicator]:
              field_list.append(field[:4] + (field_positions_global.pop(0),))
  
      return field_list
docs: Sort a set of fields by their indicators.
  
      Return a sorted list with correct global field positions.