code: def handle_pi(self, text):
          
          if text[:3] == "xml":
              text = u"xml version='1.0' encoding='%SOUP-ENCODING%'"
          self._toStringSubclass(text, ProcessingInstruction)
docs: Handle a processing instruction as a ProcessingInstruction
          object, possibly one with a %SOUP-ENCODING% slot into which an
          encoding will be plugged later.