Re-apply type annotations from .pyi stubs to your codebase.

It's smart enough to do the following:
- reapply typing imports
- reapply function argument annotations
- reapply function return value annotations
- reapply method argument and return value annotations
- reapply function-level variable annotations
- reapply module-level name annotations
- reapply module-level type aliases
- reapply class-level field annotations
- reapply instance-level field annotations
- validate existing source annotations against the .pyi file
- validate source function signatures against the .pyi file
- read function signature type comments in .pyi files
- read variable type comments in .pyi files
- consider existing source type comments as annotations
- remove duplicate type comments from source when annotations are applied
- normalize remaining type comments in the source to annotations; this is done
  even if the corresponding .pyi file is missing

WWW: https://github.com/ambv/retype