diff --git a/pytorch3d/loss/mesh_normal_consistency.py b/pytorch3d/loss/mesh_normal_consistency.py
index 59ab9ce8..8e55c01f 100644
--- a/pytorch3d/loss/mesh_normal_consistency.py
+++ b/pytorch3d/loss/mesh_normal_consistency.py
@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 
 
 def mesh_normal_consistency(meshes):
diff --git a/pytorch3d/loss/point_mesh_distance.py b/pytorch3d/loss/point_mesh_distance.py
index 5b1edc5a..c9f7b3bb 100644
--- a/pytorch3d/loss/point_mesh_distance.py
+++ b/pytorch3d/loss/point_mesh_distance.py
@@ -4,7 +4,6 @@
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
 
-# pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
 from pytorch3d import _C
 from pytorch3d.structures import Meshes, Pointclouds
 from torch.autograd import Function
diff --git a/pytorch3d/ops/graph_conv.py b/pytorch3d/ops/graph_conv.py
index 893faddf..3dff5e29 100644
--- a/pytorch3d/ops/graph_conv.py
+++ b/pytorch3d/ops/graph_conv.py
@@ -7,7 +7,7 @@
 
 import torch
 import torch.nn as nn
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from torch.autograd import Function
 from torch.autograd.function import once_differentiable
 
diff --git a/pytorch3d/ops/interp_face_attrs.py b/pytorch3d/ops/interp_face_attrs.py
index bf083229..52ddcc95 100644
--- a/pytorch3d/ops/interp_face_attrs.py
+++ b/pytorch3d/ops/interp_face_attrs.py
@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from torch.autograd import Function
 from torch.autograd.function import once_differentiable
 
diff --git a/pytorch3d/ops/knn.py b/pytorch3d/ops/knn.py
index cf3cef24..403ddfbe 100644
--- a/pytorch3d/ops/knn.py
+++ b/pytorch3d/ops/knn.py
@@ -8,7 +8,7 @@ from collections import namedtuple
 from typing import Union
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from torch.autograd import Function
 from torch.autograd.function import once_differentiable
 
@@ -58,7 +58,6 @@ class _knn_points(Function):
                 in p2 has fewer than K points and where a cloud in p1 has fewer than P1 points.
         """
 
-        # pyre-fixme[16]: Module `pytorch3d` has no attribute `_C`.
         idx, dists = _C.knn_points_idx(p1, p2, lengths1, lengths2, K, version)
 
         # sort KNN in ascending order if K > 1
@@ -74,6 +73,7 @@ class _knn_points(Function):
                 dists[mask] = 0
             else:
                 dists, sort_idx = dists.sort(dim=2)
+            # pyre-fixme[16]: `Tensor` has no attribute `gather`.
             idx = idx.gather(2, sort_idx)
 
         ctx.save_for_backward(p1, p2, lengths1, lengths2, idx)
diff --git a/pytorch3d/ops/mesh_face_areas_normals.py b/pytorch3d/ops/mesh_face_areas_normals.py
index 79f937d2..11f9c9d8 100644
--- a/pytorch3d/ops/mesh_face_areas_normals.py
+++ b/pytorch3d/ops/mesh_face_areas_normals.py
@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from torch.autograd import Function
 from torch.autograd.function import once_differentiable
 
diff --git a/pytorch3d/ops/packed_to_padded.py b/pytorch3d/ops/packed_to_padded.py
index e1eec9dd..639b0062 100644
--- a/pytorch3d/ops/packed_to_padded.py
+++ b/pytorch3d/ops/packed_to_padded.py
@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from torch.autograd import Function
 from torch.autograd.function import once_differentiable
 
diff --git a/pytorch3d/renderer/blending.py b/pytorch3d/renderer/blending.py
index 7c0ba385..e177d793 100644
--- a/pytorch3d/renderer/blending.py
+++ b/pytorch3d/renderer/blending.py
@@ -8,7 +8,7 @@
 from typing import NamedTuple, Sequence, Union
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 
 
 # Example functions for blending the top K colors per pixel using the outputs
diff --git a/pytorch3d/renderer/compositing.py b/pytorch3d/renderer/compositing.py
index f11e80b7..31be1443 100644
--- a/pytorch3d/renderer/compositing.py
+++ b/pytorch3d/renderer/compositing.py
@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 
 
 # Example functions for blending the top K features per pixel using the outputs
diff --git a/pytorch3d/renderer/mesh/rasterize_meshes.py b/pytorch3d/renderer/mesh/rasterize_meshes.py
index 492b0673..cc65fbe0 100644
--- a/pytorch3d/renderer/mesh/rasterize_meshes.py
+++ b/pytorch3d/renderer/mesh/rasterize_meshes.py
@@ -9,7 +9,7 @@ from typing import List, Optional, Tuple, Union
 
 import numpy as np
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 
 from .clip import (
     ClipFrustum,
diff --git a/pytorch3d/renderer/points/pulsar/renderer.py b/pytorch3d/renderer/points/pulsar/renderer.py
index 1c4acb8f..d3b7414c 100644
--- a/pytorch3d/renderer/points/pulsar/renderer.py
+++ b/pytorch3d/renderer/points/pulsar/renderer.py
@@ -16,7 +16,7 @@ import warnings
 from typing import Optional, Tuple, Union
 
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from pytorch3d.transforms import axis_angle_to_matrix, rotation_6d_to_matrix
 
 
diff --git a/pytorch3d/renderer/points/rasterize_points.py b/pytorch3d/renderer/points/rasterize_points.py
index 801b38f2..443c83cd 100644
--- a/pytorch3d/renderer/points/rasterize_points.py
+++ b/pytorch3d/renderer/points/rasterize_points.py
@@ -8,7 +8,7 @@ from typing import List, Optional, Tuple, Union
 
 import numpy as np
 import torch
-from pytorch3d import _C  # pyre-fixme[21]: Could not find name `_C` in `pytorch3d`.
+from pytorch3d import _C
 from pytorch3d.renderer.mesh.rasterize_meshes import pix_to_non_square_ndc