> But knowing your pre-conditions an post-conditions for your isolated parts of your code is important. Design-by-Contract[0] is a formalization of this concep

> But knowing your pre-conditions an post-conditions for your isolated parts of your code is important. Design-by-Contract[0] is a formalization of this concept and well worth considering when working in code using mutable types. In addition to pre/post conditions, DbC also reifies class invariants (which transcend method definitions). 0 - https://en.wikipedia.org/wiki/Design_by_contract https://en.wikipedia.org/wiki/Design_by_contract