fix(tokenizers-simple): set model to None to avoid serialization issues (#1867)

Author: collindutter

griptape/tokenizers/base_tokenizer.py

@@ -30,7 +30,7 @@ def max_output_tokens(self) -> int:
         return self._default_max_output_tokens()
 
     def __attrs_post_init__(self) -> None:
-        if hasattr(self, "model"):
+        if self.model is not None:
             if self.max_input_tokens is None:
                 self.max_input_tokens = self._default_max_input_tokens()
 

griptape/tokenizers/simple_tokenizer.py

@@ -7,7 +7,7 @@
 
 @define()
 class SimpleTokenizer(BaseTokenizer):
-    model: str = field(init=False, kw_only=True)
+    model: str | None = field(init=False, default=None, kw_only=True)
     characters_per_token: int = field(kw_only=True)
 
     def count_tokens(self, text: str) -> int: