Python chat streaming (#1127)

* Support streaming in chat session

* Uncommented tests

gpt4all-bindings/python/docs/gpt4all_python.md

@@ -64,7 +64,6 @@ Use the GPT4All `chat_session` context manager to hold chat conversations with t
        }
     ]
     ```
-
 When using GPT4All models in the chat_session context:
 
 - The model is given a prompt template which makes it chatty.
@@ -79,7 +78,7 @@ When using GPT4All models in the chat_session context:
 ### Streaming Generations
 To interact with GPT4All responses as the model generates, use the `streaming = True` flag during generation.
 
-=== "GPT4All Example"
+=== "GPT4All Streaming Example"
     ``` py
     from gpt4all import GPT4All
     model = GPT4All("orca-mini-3b.ggmlv3.q4_0.bin")
@@ -93,4 +92,22 @@ To interact with GPT4All responses as the model generates, use the `streaming =
     [' Paris', ' is', ' a', ' city', ' that', ' has', ' been', ' a', ' major', ' cultural', ' and', ' economic', ' center', ' for', ' over', ' ', '2', ',', '0', '0']
     ```
 
+#### Streaming and Chat Sessions
+When streaming tokens in a chat session, you must manually handle collection and updating of the chat history.
+
+```python
+from gpt4all import GPT4All
+model = GPT4All("orca-mini-3b.ggmlv3.q4_0.bin")
+
+with model.chat_session():
+    tokens = list(model.generate(prompt='hello', top_k=1, streaming=True))
+    model.current_chat_session.append({'role': 'assistant', 'content': ''.join(tokens)})
+
+    tokens = list(model.generate(prompt='write me a poem about dogs', top_k=1, streaming=True))
+    model.current_chat_session.append({'role': 'assistant', 'content': ''.join(tokens)})
+
+    print(model.current_chat_session)
+```
+
+
 ::: gpt4all.gpt4all.GPT4All

gpt4all-bindings/python/gpt4all/gpt4all.py

@@ -210,9 +210,6 @@ class GPT4All:
         if n_predict is not None:
             generate_kwargs['n_predict'] = n_predict
 
-        if streaming and self._is_chat_session_activated:
-            raise NotImplementedError("Streaming tokens in a chat session is not currently supported.")
-
         if self._is_chat_session_activated:
             self.current_chat_session.append({"role": "user", "content": prompt})
             generate_kwargs['prompt'] = self._format_chat_prompt_template(messages=self.current_chat_session)

gpt4all-bindings/python/gpt4all/tests/test_gpt4all.py

@@ -25,11 +25,13 @@ def test_inference():
     assert len(tokens) > 0
 
     with model.chat_session():
-        try:
-            response = model.generate(prompt='hello', top_k=1, streaming=True)
-            assert False
-        except NotImplementedError:
-            assert True
+        tokens = list(model.generate(prompt='hello', top_k=1, streaming=True))
+        model.current_chat_session.append({'role': 'assistant', 'content': ''.join(tokens)})
+
+        tokens = list(model.generate(prompt='write me a poem about dogs', top_k=1, streaming=True))
+        model.current_chat_session.append({'role': 'assistant', 'content': ''.join(tokens)})
+
+        print(model.current_chat_session)
 
 
 def do_long_input(model):