code: def _read_token(self) -> bytes:
      assert self.fp is not None
  
      token = b""
      while (
          len(token) <= 10
      ):  # read until next whitespace or limit of 10 characters
          c = self.fp.read(1)
          if not c:
              break
          elif c in b_whitespace:  # token ended
              if not token:
                  # skip whitespace at start
                  continue
              break
          elif c == b"#":
              # ignores rest of the line; stops at CR, LF or EOF
              while self.fp.read(1) not in b"\r\n":
                  pass
              continue
          token += c
      if not token:
          # Token was not even 1 byte
          msg = "Reached EOF while reading header"
          raise ValueError(msg)
      elif len(token) > 10:
          msg = f"Token too long in file header: {token.decode()}"
          raise ValueError(msg)
      return token
  
imports: from __future__ import annotations
  import math
  from io import BytesIO
  from .None import Image, ImageFile
  from ._binary import i16be
  from ._binary import o8
  from ._binary import o32le
label_desc: Use image node_id 2 for calling the PpmImageFile obj's underlying member method code with example usage: obj._read_token() and returns: token