diff --git a/mmseg/models/backbones/fast_scnn.py b/mmseg/models/backbones/fast_scnn.py
index d69bc5bed..522411ac7 100644
--- a/mmseg/models/backbones/fast_scnn.py
+++ b/mmseg/models/backbones/fast_scnn.py
@@ -10,7 +10,7 @@ from ..builder import BACKBONES
 
 
 class LearningToDownsample(nn.Module):
-    """Learning to downsample module"""
+    """Learning to downsample module."""
 
     def __init__(self,
                  in_channels,
@@ -53,7 +53,7 @@ class LearningToDownsample(nn.Module):
 
 
 class GlobalFeatureExtractor(nn.Module):
-    """Global feature extractor module"""
+    """Global feature extractor module."""
 
     def __init__(self,
                  in_channels=64,
@@ -115,7 +115,7 @@ class GlobalFeatureExtractor(nn.Module):
 
 
 class FeatureFusionModule(nn.Module):
-    """Feature fusion module"""
+    """Feature fusion module."""
 
     def __init__(self,
                  higher_in_channels,
@@ -188,7 +188,6 @@ class FastSCNN(nn.Module):
                  norm_cfg=dict(type='BN'),
                  act_cfg=dict(type='ReLU'),
                  align_corners=False):
-
         """Fast-SCNN Backbone.
         Args:
             in_channels(int): Number of input image channels. Default=3 (RGB)
@@ -196,28 +195,35 @@ class FastSCNN(nn.Module):
             downsample_dw_channels1(int): Number of output channels after
                 the first conv layer in Learning-To-Downsample (LTD) module.
 
-            downsample_dw_channels2(int): Number of output channels after the second conv layer in LTD.
+            downsample_dw_channels2(int): Number of output channels
+                after the second conv layer in LTD.
 
-            global_in_channels(int): Number of input channels of Global Feature Extractor(GFE).
+            global_in_channels(int): Number of input channels of
+                Global Feature Extractor(GFE).
                 Equal to number of output channels of LTD.
 
-            global_block_channels(tuple): Tuple of integers that describe the output channels for
-                each of the MobileNet-v2 bottleneck residual blocks in GFE.
+            global_block_channels(tuple): Tuple of integers that describe
+                the output channels for each of the MobileNet-v2 bottleneck
+                residual blocks in GFE.
 
             global_out_channels(int): Number of output channels of GFE.
 
-            higher_in_channels(int): Number of input channels of the higher resolution branch in FFM.
+            higher_in_channels(int): Number of input channels of the higher
+                resolution branch in FFM.
                 Equal to global_in_channels.
 
-            lower_in_channels(int): Number of input channels of  the lower resolution branch in FFM.
+            lower_in_channels(int): Number of input channels of  the lower
+                resolution branch in FFM.
                 Equal to global_out_channels.
 
             fusion_out_channels(int): Number of output channels of FFM.
 
-            scale_factor(int): The upsampling factor of the higher resolution branch in FFM.
+            scale_factor(int): The upsampling factor of the higher resolution
+                branch in FFM.
                 Equal to the downsampling factor in GFE.
 
-            out_indices(tuple): Tuple of indices of list [higher_res_features, lower_res_features, fusion_output].
+            out_indices(tuple): Tuple of indices of list
+                [higher_res_features, lower_res_features, fusion_output].
                 Often set to (0,1,2) to enable aux. heads.
 
             conv_cfg (dict|None): Config of conv layers.
@@ -228,11 +234,14 @@ class FastSCNN(nn.Module):
 
         super(FastSCNN, self).__init__()
         if global_in_channels != higher_in_channels:
-            raise AssertionError('Global Input Channels must be the same with Higher Input Channels!')
+            raise AssertionError('Global Input Channels must be the same \
+                                 with Higher Input Channels!')
         elif global_out_channels != lower_in_channels:
-            raise AssertionError('Global Output Channels must be the same with Lower Input Channels!')
+            raise AssertionError('Global Output Channels must be the same \
+                                with Lower Input Channels!')
         if scale_factor != 4:
-            raise AssertionError('Scale-factor must compensate the downsampling factor in the GFE module!')
+            raise AssertionError('Scale-factor must compensate the \
+                            downsampling factor in the GFE module!')
 
         self.in_channels = in_channels
         self.downsample_dw_channels1 = downsample_dw_channels1
diff --git a/mmseg/models/decode_heads/sep_fcn_head.py b/mmseg/models/decode_heads/sep_fcn_head.py
index d93c246f7..c7030b2cb 100644
--- a/mmseg/models/decode_heads/sep_fcn_head.py
+++ b/mmseg/models/decode_heads/sep_fcn_head.py
@@ -5,7 +5,8 @@ from .fcn_head import FCNHead
 
 @HEADS.register_module()
 class SepFCNHead(FCNHead):
-    """Depthwise-Separable Fully Convolutional Network for Semantic Segmentation
+    """Depthwise-Separable Fully Convolutional Network for Semantic
+    Segmentation.
 
     This head is implemented according to Fast-SCNN.
     Args:
@@ -16,7 +17,8 @@ class SepFCNHead(FCNHead):
         concat_input(bool): Whether to concatenate original decode input into
             the result of consecutive convolution layers.
 
-        num_classes(int): Used to determine the dimension of final prediction tensor.
+        num_classes(int): Used to determine the dimension of
+            final prediction tensor.
 
         in_index(int): Correspond with 'out_indices' in FastSCNN backbone.
 
@@ -24,7 +26,8 @@ class SepFCNHead(FCNHead):
 
         align_corners (bool): align_corners argument of F.interpolate.
 
-        loss_decode(dict): Config of loss type and some relevant additional options.
+        loss_decode(dict): Config of loss type and some
+            relevant additional options.
     """
 
     def __init__(self, **kwargs):
diff --git a/tests/test_models/test_backbone.py b/tests/test_models/test_backbone.py
index 282550179..c030464f0 100644
--- a/tests/test_models/test_backbone.py
+++ b/tests/test_models/test_backbone.py
@@ -4,7 +4,7 @@ from mmcv.ops import DeformConv2dPack
 from mmcv.utils.parrots_wrapper import _BatchNorm
 from torch.nn.modules import AvgPool2d, GroupNorm
 
-from mmseg.models.backbones import ResNet, ResNetV1d, ResNeXt, FastSCNN
+from mmseg.models.backbones import FastSCNN, ResNet, ResNetV1d, ResNeXt
 from mmseg.models.backbones.resnet import BasicBlock, Bottleneck
 from mmseg.models.backbones.resnext import Bottleneck as BottleneckX
 from mmseg.models.utils import ResLayer
@@ -680,11 +680,9 @@ def test_fastscnn_backbone():
     feat = model(imgs)
 
     assert len(feat) == 3
-    assert feat[0].shape == torch.Size([num_batch_picts, 64, 128, 256])   # higher-res
-    assert feat[1].shape == torch.Size([num_batch_picts, 128, 32, 64])    # lower-res
-    assert feat[2].shape == torch.Size([num_batch_picts, 128, 128, 256])  # FFM output
-
-
-
-
-
+    # higher-res
+    assert feat[0].shape == torch.Size([num_batch_picts, 64, 128, 256])
+    # lower-res
+    assert feat[1].shape == torch.Size([num_batch_picts, 128, 32, 64])
+    # FFM output
+    assert feat[2].shape == torch.Size([num_batch_picts, 128, 128, 256])