code: def __init__(self, parser_obj):
      self.parser_obj = parser_obj
      self.length = 0
      self.ref_id = -1
      self.ref_list = []
      self.names_defined = False
  
imports: import contextlib
  import gzip
  import json
  import re
label_desc: Use image node_id 1 to create a new LoopMMCIF object  with example: obj = LoopMMCIF(parser_obj)