code: def _open(self):
      sig = self.fp.read(4)
      if sig == b"\xff\x4f\xff\x51":
          self.codec = "j2k"
          self._size, self.mode = _parse_codestream(self.fp)
      else:
          sig = sig + self.fp.read(8)
  
          if sig == b"\x00\x00\x00\x0cjP  \x0d\x0a\x87\x0a":
              self.codec = "jp2"
              header = _parse_jp2_header(self.fp)
              self._size, self.mode, self.custom_mimetype = header
          else:
              raise SyntaxError("not a JPEG 2000 file")
  
      if self.size is None or self.mode is None:
          raise SyntaxError("unable to determine size/mode")
  
      self.reduce = 0
      self.layers = 0
  
      fd = -1
      length = -1
  
      try:
          fd = self.fp.fileno()
          length = os.fstat(fd).st_size
      except Exception:
          fd = -1
          try:
              pos = self.fp.tell()
              self.fp.seek(0, io.SEEK_END)
              length = self.fp.tell()
              self.fp.seek(pos)
          except Exception:
              length = -1
  
      self.tile = [
          (
              "jpeg2k",
              (0, 0) + self.size,
              0,
              (self.codec, self.reduce, self.layers, fd, length),
          )
      ]
  
file_path: catboost/contrib/python/Pillow/py2/PIL/Jpeg2KImagePlugin.py
imports: import io
  import os
  import struct
  from .None import Image, ImageFile
label_desc: Use image node_id 1 for calling the Jpeg2KImageFile obj's underlying member method code with example usage: obj._open() without return types