code: def __get_default_structure_ids():
      '''COMMENT'''
      if len(__DEFAULT_STRUCTURE_IDS) == 0:
          filename = get_file('default_structures.tsv')
  
          with io.open(filename, 'r', encoding='cp1252') as textfile:
              next(textfile)
  
              for line in textfile:
                  tokens = line.strip().split('\t')
                  __DEFAULT_STRUCTURE_IDS.append(int(tokens[1]))
  
      return __DEFAULT_STRUCTURE_IDf __get_default_structure_ids():
      '''COMMENT'''
      if len(__DEFAULT_STRUCTURE_IDS) == 0:
          filename = get_file('default_structures.tsv')
  
          with io.open(filename, 'r', encoding='cp1252') as textfile:
              next(textfile)
  
              for line in textfile:
                  tokens = line.strip().split('\t')
                  __DEFAULT_STRUCTURE_IDS.append(int(tokens[1]))
  
      return __DEFAULT_STRUCTURE_IDS
docs: COMMENT