presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitNormalize
class AstBuilder:    @Override
    public Node visitNormalize(SqlBaseParser.NormalizeContext context)
    {
        Expression str = (Expression) visit(context.valueExpression());
        String normalForm = Optional.ofNullable(context.normalForm()).map(ParserRuleContext::getText).orElse("NFC");
        return new FunctionCall(
                getLocation(context),
                QualifiedName.of(ImmutableList.of(new Identifier("normalize", true))), // delimited to avoid ambiguity with NORMALIZE SQL construct
                ImmutableList.of(str, new StringLiteral(getLocation(context), normalForm)));
    }