---
enhancements:
  - |
    Haystack's core modules are now
    ["type complete"](https://typing.python.org/en/latest/guides/libraries.html#how-much-of-my-library-needs-types),
    meaning that all function parameters and return types are explicitly
    annotated. This increases the usefulness of the newly added `py.typed`
    marker and sidesteps  differences in type inference between the various
    type checker implementations.
