In the base class, the signature is defined as:
type: (str) -> str
Further, the docstring says:
Raises RemoteNotFoundError if the repository does not have a remote
url configured.
However, some subclasses were returning None instead of raising
RemoteNotFoundError. This violated the type signature and forced calling
code to handle multiple error paradigms.
Now, all subclasses implement the base's signature.
This allowed simplifying some call sites as they can assume None will
not be returned.
This mismatch was noticed while trying to remove "mypy:
disallow-untyped-defs=False" comments.