class_docstr: PNG chunk container (for use with save(pnginfo=))
class_docstr_tok: ["PNG","chunk","container","(","for","use","with","save","(","pnginfo=",")",")"]
docstr: Appends an arbitrary chunk. Use with caution.
  
  :param cid: a byte string, 4 bytes long.
  :param data: a byte string of the encoded data
docstr_tok: ["Appends","an","arbitrary","chunk",".","Use","with","caution",".",":","param","cid",":","a","byte","string",",","4","bytes","long",".",":","param","data",":","a","byte","string","of","the","encoded","data"]
code: def add(self, cid, data):
      """Appends an arbitrary chunk. Use with caution.
  
      :param cid: a byte string, 4 bytes long.
      :param data: a byte string of the encoded data
  
      """
  
      self.chunks.append((cid, data))
  
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 2 for calling the PngInfo obj's underlying member method code with example usage: obj.add(cid, data) without return types