presto-main/src/main/java/io/prestosql/operator/scalar/JsonStringToMapCast.java/JsonStringToMapCast/JsonStringToMapCast
class JsonStringToMapCast:    private JsonStringToMapCast()
    {
        super(new FunctionMetadata(
                new Signature(
                        JSON_STRING_TO_MAP_NAME,
                        ImmutableList.of(comparableTypeParameter("K"), typeVariable("V")),
                        ImmutableList.of(),
                        mapType(new TypeSignature("K"), new TypeSignature("V")),
                        ImmutableList.of(VARCHAR.getTypeSignature()),
                        false),
                true,
                ImmutableList.of(new FunctionArgumentDefinition(false)),
                true,
                true,
                "",
                SCALAR));
    }