Deduplicate choices

Ensure choices are not duplicated, as that makes StrEnum impossible to
resolve. Each element should only exist once.

python/cog/predictor.py

@@ -355,6 +355,8 @@ def get_input_create_model_kwargs(signature: inspect.Signature) -> Dict[str, Any
         # passed automatically as 'enum' in the schema
         if choices:
             if InputType == str and isinstance(choices, Iterable):  # noqa: E721
+                # Deduplicate choices
+                choices = list(set(choices))
 
                 class StringEnum(str, enum.Enum):
                     pass

python/tests/server/fixtures/input_choices.py

@@ -2,6 +2,6 @@
 
 
 class Predictor(BasePredictor):
-    def predict(self, text: str = Input(choices=["foo", "bar"])) -> str:
+    def predict(self, text: str = Input(choices=["foo", "bar", "foo"])) -> str:
         assert type(text) == str
         return text