code: def buildQName(ncname, prefix, memory, len):
      
      ret = libxml2mod.xmlBuildQName(ncname, prefix, memory, len)
      return ret
docs: Builds the QName @prefix:@ncname in @memory if there is
        enough space and prefix is not None nor empty, otherwise
        allocate a new string. If prefix is None or empty it
         returns ncname.