presto-main/src/main/java/io/prestosql/metadata/PolymorphicScalarFunctionBuilder.java/PolymorphicScalarFunctionBuilder/isOperator
class PolymorphicScalarFunctionBuilder:    private static boolean isOperator(Signature signature)
    {
        for (OperatorType operator : OperatorType.values()) {
            if (signature.getName().equals(mangleOperatorName(operator))) {
                return true;
            }
        }

        return false;
    }