Clan-app/api: error on {unknown api method, mismatching parameter name}

pkgs/clan-cli/clan_cli/api/__init__.py

@@ -228,8 +228,17 @@ API.register(open_file)
         from inspect import signature
 
         func = self._registry.get(method_name, None)
-        if func:
+        if not func:
+            msg = f"API Method {method_name} not found in registry. Available methods: {list(self._registry.keys())}"
+            raise ClanError(msg)
+
         sig = signature(func)
+
+        # seems direct 'key in dict' doesnt work here
+        if arg_name not in sig.parameters.keys():  # noqa: SIM118
+            msg = f"Argument {arg_name} not found in api method '{method_name}'. Avilable arguments: {list(sig.parameters.keys())}"
+            raise ClanError(msg)
+
         param = sig.parameters.get(arg_name)
         if param:
             param_class = param.annotation