code: def _open(self):
      s = BitStream(self.fp)
  
      if s.read(32) != 0x1B3:
          msg = "not an MPEG file"
          raise SyntaxError(msg)
  
      self._mode = "RGB"
      self._size = s.read(12), s.read(12)
  
file_path: pillow/src/PIL/MpegImagePlugin.py
imports: from __future__ import annotations
  from .None import Image, ImageFile
  from ._binary import i8
label_desc: Use image node_id 1 for calling the MpegImageFile obj's underlying member method code with example usage: obj._open() without return types