refactor _call_model_cached function implementation

evoprompt/models.py

@@ -44,11 +44,16 @@ class LLMModel(ABC):
         self.kwargs = kwargs
 
         # set up caching for model calls
+        self._call_model_cached = None
         if not options.disable_cache:
             cache = Cache(Path(".cache_dir", self.model_cache_key))
-            self._call_model_cached = cache.memoize(typed=True, ignore=[0, "func"])(
-                self._call_model_cached
-            )
+
+            @cache.memoize(typed=True, ignore=["func"])
+            def _call_function(func, *args, **kwargs):
+                # `cache_key` is added to the cache key (e.g., to distinguish between different models), but it is not used in the function
+                return func(*args, **kwargs)
+
+            self._call_model_cached = _call_function
 
     @abstractmethod
     def build_model_input(
@@ -114,16 +119,11 @@ class LLMModel(ABC):
             warnings.warn("Caching is disabled when a grammar is provided.")
             use_cache = False
 
-        if use_cache:
-            # use cached function call
+        if use_cache and self._call_model_cached is not None:
             return self._call_model_cached(model_completion_fn, **kwargs)
         else:
             return model_completion_fn(**kwargs)
 
-    def _call_model_cached(self, func, *args, **kwargs):
-        # `cache_key` is added to the cache key (e.g., to distinguish between different models), but it is not used in the function
-        return func(*args, **kwargs)
-
     @property
     def model_cache_key(self):
         unique_options_key = json.dumps(