code: def assert_files(self, folder):
      files_needed = self.JSONL_PHASE_ONE_FILES
      phase_one = True
      for file in files_needed:
          try:
              assert PathManager.exists(
                  os.path.join(folder, "data", file)
              ), f"{file} doesn't exist in {folder}"
          except AssertionError:
              phase_one = False
  
      if not phase_one:
          files_needed = self.JSONL_PHASE_TWO_FILES
          for file in files_needed:
              assert PathManager.exists(
                  os.path.join(folder, "data", file)
              ), f"{file} doesn't exist in {folder}"
      else:
          warnings.warn(
              "You are on Phase 1 of the Hateful Memes Challenge. "
              "Please update to Phase 2"
          )
  
      files_needed = self.IMAGE_FILES
  
      exists = False
  
      for file in files_needed:
          exists = exists or PathManager.exists(
              os.path.join(folder, "data", file)
          )
  
      if not exists:
          raise AssertionError(
              "Neither img or img.tar.gz exists in current zip"
          )
  
      return phase_one
  
file_path: mmf/mmf_cli/hm_convert.py
imports: import argparse
  import hashlib
  import os
  import subprocess
  import warnings
  import zipfile
  from mmf.utils.configuration import Configuration
  from mmf.utils.download import copy, decompress, move
  from mmf.utils.file_io import PathManager
label_desc: Use image node_id 2 for calling the HMConverter obj's underlying member method code with example usage: obj.assert_files(folder) and returns: phase_one