remove is_chat argument

evoprompt/task/task.py

@@ -318,6 +318,7 @@ class Task(metaclass=ABCMeta):
             prompt_appendix=self._get_prompt_text_for_datum(datum),
             # grammar can be applied to constrain the model output
             grammar=self._get_grammar(datum) if self.use_grammar else None,
+            # we use cached completions to speed up the process although we loose the non-deterministic behavior of LMs, but we're ok with a single result
             use_cache=True,
         )