code: def _read_block(self):
      return self.fd.read(ImageFile.SAFEBLOCK)
  
imports: from .None import Image, ImageFile
  from ._binary import i16be
  from ._binary import o8
  from ._binary import o32le
label_desc: Use image node_id 1 for calling the PpmPlainDecoder obj's underlying member method code with example usage: obj._read_block() and returns: self