diff --git a/prototorch/datasets/__init__.py b/prototorch/datasets/__init__.py
index 1d61061..096fc6f 100644
--- a/prototorch/datasets/__init__.py
+++ b/prototorch/datasets/__init__.py
@@ -1,6 +1,12 @@
-"""ProtoTorch datasets."""
+"""ProtoTorch datasets"""
 
 from .abstract import NumpyDataset
-from .sklearn import Blobs, Circles, Iris, Moons, Random
+from .sklearn import (
+    Blobs,
+    Circles,
+    Iris,
+    Moons,
+    Random,
+)
 from .spiral import Spiral
 from .tecator import Tecator
diff --git a/prototorch/datasets/abstract.py b/prototorch/datasets/abstract.py
index e941c95..dac8f8c 100644
--- a/prototorch/datasets/abstract.py
+++ b/prototorch/datasets/abstract.py
@@ -1,10 +1,11 @@
-"""ProtoTorch abstract dataset classes.
+"""ProtoTorch abstract dataset classes
 
-Based on `torchvision.VisionDataset` and `torchvision.MNIST`
+Based on `torchvision.VisionDataset` and `torchvision.MNIST`.
 
 For the original code, see:
 https://github.com/pytorch/vision/blob/master/torchvision/datasets/vision.py
 https://github.com/pytorch/vision/blob/master/torchvision/datasets/mnist.py
+
 """
 
 import os
@@ -12,15 +13,6 @@ import os
 import torch
 
 
-class NumpyDataset(torch.utils.data.TensorDataset):
-    """Create a PyTorch TensorDataset from NumPy arrays."""
-    def __init__(self, data, targets):
-        self.data = torch.Tensor(data)
-        self.targets = torch.LongTensor(targets)
-        tensors = [self.data, self.targets]
-        super().__init__(*tensors)
-
-
 class Dataset(torch.utils.data.Dataset):
     """Abstract dataset class to be inherited."""
 
@@ -44,7 +36,7 @@ class ProtoDataset(Dataset):
     training_file = "training.pt"
     test_file = "test.pt"
 
-    def __init__(self, root, train=True, download=True, verbose=True):
+    def __init__(self, root="", train=True, download=True, verbose=True):
         super().__init__(root)
         self.train = train  # training set or test set
         self.verbose = verbose
@@ -96,3 +88,12 @@ class ProtoDataset(Dataset):
 
     def _download(self):
         raise NotImplementedError
+
+
+class NumpyDataset(torch.utils.data.TensorDataset):
+    """Create a PyTorch TensorDataset from NumPy arrays."""
+    def __init__(self, data, targets):
+        self.data = torch.Tensor(data)
+        self.targets = torch.LongTensor(targets)
+        tensors = [self.data, self.targets]
+        super().__init__(*tensors)
diff --git a/prototorch/utils/colors.py b/prototorch/utils/colors.py
index 07e2d5d..61ad1a0 100644
--- a/prototorch/utils/colors.py
+++ b/prototorch/utils/colors.py
@@ -1,4 +1,4 @@
-"""ProtoFlow color utilities."""
+"""ProtoFlow color utilities"""
 
 
 def hex_to_rgb(hex_values):