Hello, everyone,
I'd like to construct a type which contains some functions that I would
like to give value later (as attributes of instance).
I define this type as:
```
type Objective
f::Any
g::Any
end
```
where `f` is the objective function and `g` is the derivative.My question is: 1) instead of define them as `Any`, is there any other more specific type? 2) is there any better design pattern?
