presto-parser/src/main/java/io/prestosql/sql/tree/JoinUsing.java/JoinUsing/JoinUsing
class JoinUsing:    public JoinUsing(List<Identifier> columns)
    {
        requireNonNull(columns, "columns is null");
        checkArgument(!columns.isEmpty(), "columns is empty");
        this.columns = ImmutableList.copyOf(columns);
    }