fix docs strings

Author: jonathanedey

firebase_admin/firestore.py

@@ -42,17 +42,18 @@ def client(app: Optional[App] = None, database_id: Optional[str] = None) -> fire
     """Returns a client that can be used to interact with Google Cloud Firestore.
 
     Args:
-      app: An App instance (optional).
-      database_id: The database ID of the Google Cloud Firestore database to be used.
-          Defaults to the default firestore database if not specified or empty string (optional).
+        app: An App instance (optional).
+        database_id: The database ID of the Google Cloud Firestore database to be used.
+            Defaults to the default Firestore database ID if not specified or an empty string
+            (optional).
 
     Returns:
-      google.cloud.firestore.Firestore: A `Firestore Client`_.
+        google.cloud.firestore.Firestore: A `Firestore Client`_.
 
     Raises:
-      ValueError: If the database ID is not None or a string or a project ID is not specified
-          either via options, credentials or environment variables, or if the specified
-          project ID is not a valid string.
+        ValueError: If the specified database ID is not a valid string, or if a project ID is not
+            specified either via options, credentials or environment variables, or if the specified
+            project ID is not a valid string.
 
     .. _Firestore Client: https://cloud.google.com/python/docs/reference/firestore/latest/\
         google.cloud.firestore_v1.client.Client

firebase_admin/firestore_async.py

@@ -44,14 +44,15 @@ def client(app: Optional[App] = None, database_id: Optional[str] = None) -> fire
     Args:
         app: An App instance (optional).
         database_id: The database ID of the Google Cloud Firestore database to be used.
-            Defaults to the default firestore database if not specified or empty string (optional).
+            Defaults to the default Firestore database ID if not specified or an empty string
+            (optional).
 
     Returns:
         google.cloud.firestore.Firestore_Async: A `Firestore Async Client`_.
 
     Raises:
-        ValueError: If the database ID is not None or a string or a project ID is not specified
-            either via options, credentials or environment variables, or if the specified
+        ValueError: If the specified database ID is not a valid string, or if a project ID is not
+            specified either via options, credentials or environment variables, or if the specified
             project ID is not a valid string.
 
     .. _Firestore Async Client: https://cloud.google.com/python/docs/reference/firestore/latest/\