code: def _open(self):
      struct.unpack("<I", self.fp.read(4))  # magic
      struct.unpack("<i", self.fp.read(4))  # version
      self._size = struct.unpack("<2i", self.fp.read(8))
      mipmap_count, format_count = struct.unpack("<2i", self.fp.read(8))
  
      self.mode = "RGB"
  
      # Only support single-format files.
      # I don't know of any multi-format file.
      assert format_count == 1
  
      format, where = struct.unpack("<2i", self.fp.read(8))
      self.fp.seek(where)
      (mipmap_size,) = struct.unpack("<i", self.fp.read(4))
  
      data = self.fp.read(mipmap_size)
  
      if format == FORMAT_DXT1:
          self.mode = "RGBA"
          self.tile = [("bcn", (0, 0) + self.size, 0, (1))]
      elif format == FORMAT_UNCOMPRESSED:
          self.tile = [("raw", (0, 0) + self.size, 0, ("RGB", 0, 1))]
      else:
          raise ValueError(
              "Invalid texture compression format: %r" % (format)
          )
  
      self.fp.close()
      self.fp = BytesIO(data)
  
file_path: catboost/contrib/python/Pillow/py2/PIL/FtexImagePlugin.py
imports: import struct
  from io import BytesIO
  from .None import Image, ImageFile
label_desc: Use image node_id 1 for calling the FtexImageFile obj's underlying member method code with example usage: obj._open() without return types