Handle empty fields in error identifier

Co-authored-by: Nate Prewitt <nate.prewitt@gmail.com>

Author: JordonPhillips

packages/smithy-aws-core/src/smithy_aws_core/aio/protocols.py

@@ -22,7 +22,8 @@ def identify(
         if self._HEADER_KEY not in response.fields:
             return None
 
-        code = response.fields[self._HEADER_KEY].values[0]
+        error_field = response.fields[self._HEADER_KEY]
+        code = error_field.values[0] if len(error_field.values) > 0 else None
         if not code:
             return None
 

packages/smithy-http/src/smithy_http/aio/protocols.py

@@ -144,7 +144,7 @@ def _is_success(
         context: TypedProperties,
         response: HTTPResponse,
     ) -> bool:
-        return 200 <= response.status <= 299
+        return 200 <= response.status < 300
 
     async def _create_error(
         self,