Is your feature request related to a problem? Please describe.
VSCode can use Python type annotations to provide a much better experience, and allow completion.

Describe the solution you'd like
function signatures should return a return type, to allow completions. For example, in firestore.py
def client() -> google.cloud.firestore.Client would allow completion on client().collection("something"), etc.

Describe alternatives you've considered
As a workaround, I'm using the following today:

from firebase_admin import firestore
from google.cloud.firestore import Client as FirestoreClient # importing the return type of firestore.client()
db: FirestoreClient = firestore.client() # Adding an annotation to my db variable, to enable completion and syntax checking

Additional context
Using the latest VSCode, with the Pylance extension.