code: def read_dumps(dump_dir):
      dump_files = os.listdir(dump_dir)
      dump_files.sort()
      all_chats = []
      for dump_fn in dump_files:
          if not dump_fn.endswith(".json"):
              continue
          read_chats = read_dump(os.path.join(dump_dir, dump_fn))
          all_chats += format_chats(read_chats)
      return all_chats
  
imports: import random
  import io
  import os
  import json
  from parlai.utils.misc import msg_to_str
label_desc: Use image node_id 15 for calling a global function with example usage: read_dumps(dump_dir) and returns: all_chats