[EXTAPI] refactor weight compression to be used by an external consumer

*lint
*added unit tests
*added typecheck
*added docstring for the api
Change-Id: Ibd4bc40d4381ac40ad2ea3d500b26c4ec565ab07
Signed-off-by: Manupa Karunaratne <manupa.karunaratne@arm.com>
diff --git a/ethosu/vela/vela.py b/ethosu/vela/vela.py
index 20bc525..1766750 100644
--- a/ethosu/vela/vela.py
+++ b/ethosu/vela/vela.py
@@ -170,7 +170,7 @@
         "--accelerator-config",
         type=str,
         default="ethos-u55-256",
-        choices=list(architecture_features.ArchitectureFeatures.accelerator_configs.keys()),
+        choices=list(architecture_features.Accelerator.member_list()),
         help="Accelerator configuration to use (default: %(default)s)",
     )
     parser.add_argument(