mypy fixes for openai_models.py

I am unhappy with this, had to duplicate some code.

llm/default_plugins/openai_models.py

@@ -299,16 +299,6 @@ def _attachment(attachment):
 
 
 class _Shared:
-    needs_key = "openai"
-    key_env_var = "OPENAI_API_KEY"
-    default_max_tokens = None
-
-    class Options(SharedOptions):
-        json_object: Optional[bool] = Field(
-            description="Output a valid JSON object {...}. Prompt must mention JSON.",
-            default=None,
-        )
-
     def __init__(
         self,
         model_id,
@@ -437,6 +427,16 @@ def build_kwargs(self, prompt, stream):
 
 
 class Chat(_Shared, Model):
+    needs_key = "openai"
+    key_env_var = "OPENAI_API_KEY"
+    default_max_tokens = None
+
+    class Options(SharedOptions):
+        json_object: Optional[bool] = Field(
+            description="Output a valid JSON object {...}. Prompt must mention JSON.",
+            default=None,
+        )
+
     def execute(self, prompt, stream, response, conversation=None):
         if prompt.system and not self.allows_system_prompt:
             raise NotImplementedError("Model does not support system prompts")
@@ -473,6 +473,16 @@ def execute(self, prompt, stream, response, conversation=None):
 
 
 class AsyncChat(_Shared, AsyncModel):
+    needs_key = "openai"
+    key_env_var = "OPENAI_API_KEY"
+    default_max_tokens = None
+
+    class Options(SharedOptions):
+        json_object: Optional[bool] = Field(
+            description="Output a valid JSON object {...}. Prompt must mention JSON.",
+            default=None,
+        )
+
     async def execute(self, prompt, stream, response, conversation=None):
         if prompt.system and not self.allows_system_prompt:
             raise NotImplementedError("Model does not support system prompts")