pat, pat.loc, pat2, pat2.loc, d)
		}
		return nil
	}); err != nil {
		return err
	}
	mux.tree.addPattern(pat, handler)
	mux.index.addPattern(pat)
	mux.patterns = append(mux.patterns, pat)
	return nil
}

// Serve accepts incoming HTTP connections on the listener l,