Yeah, I second the preference for the latter approach. It encourages more reusable components - you get to use `format_user_data` in situations which don't requ

Yeah, I second the preference for the latter approach. It encourages more reusable components - you get to use `format_user_data` in situations which don't require data validation, for example. The one downside is the second style of code is a little uglier in languages without a good function composition operator, like Python. I enjoy writing stuff like user = data |> format_user_data |> validate_user_data in languages that support the pipeline operator.