fix mismatched parameters

README.md

@@ -42,7 +42,8 @@ for message in response:
     print(message)
 
 # normal response
-response = g4f.ChatCompletion.create(model=g4f.Models.gpt_4, prompt='hi') # alterative model setting
+response = g4f.ChatCompletion.create(model=g4f.Models.gpt_4, messages=[
+                                     {"role": "user", "content": "hi"}]) # alterative model setting
 
 print(response)
 
@@ -78,4 +79,4 @@ def _create_completion(prompt: str, args...):
 
 params = f'g4f.Providers.{os.path.basename(__file__)[:-3]} supports: ' + \
     ', '.join([f"{name}: {get_type_hints(_create_completion)[name].__name__}" for name in _create_completion.__code__.co_varnames[:_create_completion.__code__.co_argcount]])
-```
+```

g4f/__init__.py

@@ -36,8 +36,8 @@ class ChatCompletion:
             
             engine = model.best_site if not provider else provider
 
-            return (engine._create_completion(messages, **kwargs)
-                    if stream else ''.join(engine._create_completion(messages, **kwargs)))
+            return (engine._create_completion(model, messages, **kwargs)
+                    if stream else ''.join(engine._create_completion(model, messages, **kwargs)))
 
         except TypeError as e:
             print(e)