code: def _guess_media_encoding(self, source):
      info = source.byteStream.info()
      if "Content-Type" in info:
          for param in info.getplist():
              if param.startswith("charset="):
                  return param.split("=", 1)[1].lower()
  
imports: import copy
  import xml.dom
  from xml.dom.NodeFilter import NodeFilter
label_desc: Use image node_id 4 for calling the DOMEntityResolver obj's underlying member method code with example usage: obj._guess_media_encoding(source) and returns: param