Fix JsonObject type for MyPy

Workaround a MyPy error by marking the driver json Object as of type
dict and indexable.

Signed-off-by: Archana <archana.madhavan@silabs.com>
Signed-off-by: Asfandyar Orakzai <asfandyar.orakzai@silabs.com>
diff --git a/scripts/generate_driver_wrappers.py b/scripts/generate_driver_wrappers.py
index 3d9be88..3c71202 100755
--- a/scripts/generate_driver_wrappers.py
+++ b/scripts/generate_driver_wrappers.py
@@ -30,7 +30,9 @@
 from mbedtls_dev import build_tree
 
 JSONSchema = NewType('JSONSchema', object)
-Driver = NewType('Driver', object)
+# The Driver is an Object, but practically it's indexable and can called a dictionary to
+# keep MyPy happy till MyPy comes with a more composite type for JsonObjects.
+Driver = NewType('Driver', dict)
 
 def render(template_path: str, driver_jsoncontext: list) -> str:
     """
@@ -63,7 +65,6 @@
     Validate the Driver JSON against an appropriate schema
     the schema passed could be that matching an opaque/ transparent driver.
     """
-
     driver_type = driverjson_data["type"]
     driver_prefix = driverjson_data["prefix"]
     try: