def add_prefix(self, ncname: str) -> None:
if ncname not in self.prefixmap:<EOL><INDENT>uri = cu.expand_uri(ncname + '<STR_LIT::>', self.curi_maps)<EOL>if uri and '<STR_LIT>' in uri:<EOL><INDENT>self.prefixmap[ncname] = uri<EOL><DEDENT>else:<EOL><INDENT>print(f"<STR_LIT>", file=sys.stderr)<EOL>self.prefixmap[ncname] = f"<STR_LIT>"<EOL><DEDENT><DEDENT>
Look up ncname and add it to the prefix map if necessary

        @param ncname: name to add