presto-parser/src/main/java/io/prestosql/sql/SqlFormatter.java/Formatter/visitDropSchema
class Formatter:        @Override
        protected Void visitDropSchema(DropSchema node, Integer context)
        {
            builder.append("DROP SCHEMA ");
            if (node.isExists()) {
                builder.append("IF EXISTS ");
            }
            builder.append(formatName(node.getSchemaName()))
                    .append(" ")
                    .append(node.isCascade() ? "CASCADE" : "RESTRICT");

            return null;
        }