diff --git a/threestudio/models/renderers/nerf_volume_renderer.py b/threestudio/models/renderers/nerf_volume_renderer.py
index ab27e476..f8a1caca 100644
--- a/threestudio/models/renderers/nerf_volume_renderer.py
+++ b/threestudio/models/renderers/nerf_volume_renderer.py
@@ -9,7 +9,11 @@
 from threestudio.models.geometry.base import BaseImplicitGeometry
 from threestudio.models.materials.base import BaseMaterial
 from threestudio.models.renderers.base import VolumeRenderer
+<<<<<<< HEAD
 from threestudio.utils.ops import chunk_batch, validate_empty_rays
+=======
+from threestudio.utils.ops import chunk_batch
+>>>>>>> TextMesh coarse stage implementation (#121)
 from threestudio.utils.typing import *
 
 
diff --git a/threestudio/models/renderers/neus_volume_renderer.py b/threestudio/models/renderers/neus_volume_renderer.py
index ca53ce25..180fc907 100644
--- a/threestudio/models/renderers/neus_volume_renderer.py
+++ b/threestudio/models/renderers/neus_volume_renderer.py
@@ -104,7 +104,9 @@ def forward(
         n_rays = rays_o_flatten.shape[0]
 
         def alpha_fn(t_starts, t_ends, ray_indices):
-            ray_indices, t_starts, t_ends = validate_empty_rays(ray_indices, t_starts, t_ends)
+            ray_indices, t_starts, t_ends = validate_empty_rays(
+                ray_indices, t_starts, t_ends
+            )
             t_starts, t_ends = t_starts[..., None], t_ends[..., None]
             t_origins = rays_o_flatten[ray_indices]
             t_positions = (t_starts + t_ends) / 2.0
@@ -153,7 +155,9 @@ def alpha_fn(t_starts, t_ends, ray_indices):
                     cone_angle=0.0,
                 )
 
-        ray_indices, t_starts_, t_ends_ = validate_empty_rays(ray_indices, t_starts_, t_ends_)
+        ray_indices, t_starts_, t_ends_ = validate_empty_rays(
+            ray_indices, t_starts_, t_ends_
+        )
         ray_indices = ray_indices.long()
         t_starts, t_ends = t_starts_[..., None], t_ends_[..., None]
         t_origins = rays_o_flatten[ray_indices]
@@ -163,7 +167,6 @@ def alpha_fn(t_starts, t_ends, ray_indices):
         positions = t_origins + t_dirs * t_positions
         t_intervals = t_ends - t_starts
 
-
         if self.training:
             geo_out = self.geometry(positions, output_normal=True)
             rgb_fg_all = self.material(
diff --git a/threestudio/utils/saving.py b/threestudio/utils/saving.py
index f68ac954..b233d151 100644
--- a/threestudio/utils/saving.py
+++ b/threestudio/utils/saving.py
@@ -9,12 +9,12 @@
 import numpy as np
 import torch
 import trimesh
+import wandb
 from matplotlib import cm
 from matplotlib.colors import LinearSegmentedColormap
 from PIL import Image, ImageDraw
 from pytorch_lightning.loggers import WandbLogger
 
-import wandb
 from threestudio.models.mesh import Mesh
 from threestudio.utils.typing import *