More detail on dedicated submodule

Hi, I'm interested in trying out this library, it looks like a great addition to the Elixir testing landscape! I was curious about this sentence in the readme: > Note that Efx generates and implements a behavior. Thus, it is recommended, to move side effects to a dedicated submodule, e.g. MyModule.Effects, to not accidentally interfere with existing behaviors. What would it look like to create a separate effects submodule? Is that only required/recommended if you want your module to define a `behaviour`?