@SuppressWarnings("unchecked")
    public static <D extends Comparable<?>> ComparablePath<D> var(D arg) {
        return Expressions.comparablePath((Class<D>) arg.getClass(), "var" + arg);
    }
Create a new variable path

@param arg alias
@param <D>
@return expression
querydsl-core/src/main/java/com/querydsl/core/alias/Alias.java