Using EF Include() with generic repository

gistfile1.cs

public IQueryable<T> FindBy(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] includes)
{
    var query = GetAll().Where(predicate);
    return includes.Aggregate(query, (current, includeProperty) => current.Include(includeProperty));
}

// Sample usage
userRepository.FindBy(x => x.Username == username, x.Roles)

How Can I get multiple navigation property