code: def URIUnescapeString(str, len, target):
      
      ret = libxml2mod.xmlURIUnescapeString(str, len, target)
      return ret
docs: Unescaping routine, but does not check that the string is
        an URI. The output is a direct unsigned char translation of
        %XX values (no encoding) Note that the length of the result
         can only be smaller or same size as the input string.