code: def _validate(prefix):
      return prefix[:4] == b"DDS "
  
file_path: catboost/contrib/python/Pillow/py2/PIL/DdsImagePlugin.py
imports: import struct
  from io import BytesIO
  from .None import Image, ImageFile
label_desc: Use image node_id 1 for calling a global function with example usage: _validate(prefix) and returns: unknown