code: def chunk_zTXt(self, pos, length):
      # compressed text
      s = ImageFile._safe_read(self.fp, length)
      try:
          k, v = s.split(b"\0", 1)
      except ValueError:
          k = s
          v = b""
      if v:
          comp_method = i8(v[0])
      else:
          comp_method = 0
      if comp_method != 0:
          raise SyntaxError(
              "Unknown compression method %s in zTXt chunk"
              % comp_method
          )
      try:
          v = _safe_zlib_decompress(v[1:])
      except ValueError:
          if ImageFile.LOAD_TRUNCATED_IMAGES:
              v = b""
          else:
              raise
      except zlib.error:
          v = b""
  
      if k:
          if py3:
              k = k.decode("latin-1", "strict")
              v = v.decode("latin-1", "replace")
  
          self.im_info[k] = self.im_text[k] = v
          self.check_text_memory(len(v))
  
      return s
  
imports: import logging
  import re
  import struct
  import zlib
  from .None import Image, ImageFile, ImagePalette
  from ._binary import i8, i16be, i32be, o16be, o32be
  from ._util import py3
label_desc: Use image node_id 14 for calling the PngStream obj's underlying member method code with example usage: obj.chunk_zTXt(pos, length) and returns: s