presto-main/src/main/java/io/prestosql/metadata/SignatureBinder.java/FunctionSolver/toTypeSignatures
class FunctionSolver:        private List<TypeSignature> toTypeSignatures(List<Type> types)
        {
            return types.stream()
                    .map(Type::getTypeSignature)
                    .collect(toImmutableList());
        }