Comment by yoyohello13

Unless you're doing greenfield, gradual typing is really the only way. I've incorporated type hinting in several legacy Python code bases with mypy and really the only sensible way is to "opt-in" one module at a time. If pyrefly doesn’t support that I think its use will be pretty limited. Unless maybe they are going for the llm code gen angle. I could see a very fast and strict type checker being useful for llm generating python scripts.