Fix pyre errors in Occlusion (pytorch#1403)

Summary:

Initial work on fixing Pyre errors in Occlusion

Reviewed By: craymichael

Differential Revision: D64677342

Author: Vivek Miglani

captum/attr/_core/occlusion.py

@@ -37,8 +37,7 @@ class Occlusion(FeatureAblation):
     /tensorflow/methods.py#L401
     """
 
-    # pyre-fixme[24]: Generic type `Callable` expects 2 type parameters.
-    def __init__(self, forward_func: Callable) -> None:
+    def __init__(self, forward_func: Callable[..., Tensor]) -> None:
         r"""
         Args:
 
@@ -58,8 +57,7 @@ def attribute(  # type: ignore
         ] = None,
         baselines: BaselineType = None,
         target: TargetType = None,
-        # pyre-fixme[2]: Parameter annotation cannot be `Any`.
-        additional_forward_args: Any = None,
+        additional_forward_args: object = None,
         perturbations_per_eval: int = 1,
         show_progress: bool = False,
     ) -> TensorOrTupleOfTensorsGeneric:
@@ -377,9 +375,7 @@ def _occlusion_mask(
         padded_tensor = torch.nn.functional.pad(
             sliding_window_tsr, tuple(pad_values)  # type: ignore
         )
-        # pyre-fixme[58]: `+` is not supported for operand types `Tuple[int]` and
-        #  `Size`.
-        return padded_tensor.reshape((1,) + padded_tensor.shape)
+        return padded_tensor.reshape((1,) + tuple(padded_tensor.shape))
 
     def _get_feature_range_and_mask(
         self, input: Tensor, input_mask: Optional[Tensor], **kwargs: Any
@@ -389,8 +385,7 @@ def _get_feature_range_and_mask(
 
     def _get_feature_counts(
         self,
-        # pyre-fixme[2]: Parameter must be annotated.
-        inputs,
+        inputs: TensorOrTupleOfTensorsGeneric,
         feature_mask: Tuple[Tensor, ...],
         **kwargs: Any,
     ) -> Tuple[int, ...]: