old_contents: import hashlib
  
  
  def md5_for_file(path_to_file: str) -> str:
      with open(path_to_file, mode='rb') as f:
          d = hashlib.md5()
          for buf in f.read(4096):
              d.update(buf)
      return d.hexdigest()
  
new_contents: import hashlib
  
  
  def md5_for_file(path_to_file: str) -> str:
      with open(path_to_file, 'rb') as f:
          d = hashlib.md5()
          for buf in f.read(4096):
              d.update(buf)
      return d.hexdigest()
  
subject: remove 'mode' argument name for open command