Format Python code with psf/black push (#345)

There appear to be some python formatting errors in
97abfa0. This pull request
uses the [psf/black](https://github.com/psf/black) formatter to fix
these issues.

tests/fixtures/__init__.py

@@ -24,5 +24,11 @@
     unet_3d_distance_run,
     hot_distance_run,
 )
-from .tasks import dummy_task, distance_task, onehot_task, six_onehot_task, hot_distance_task
+from .tasks import (
+    dummy_task,
+    distance_task,
+    onehot_task,
+    six_onehot_task,
+    hot_distance_task,
+)
 from .trainers import dummy_trainer, gunpowder_trainer

tests/fixtures/runs.py

@@ -20,6 +20,7 @@ def distance_run(
         num_iterations=10,
     )
 
+
 @pytest.fixture()
 def hot_distance_run(
     six_class_datasplit,
@@ -38,7 +39,6 @@ def hot_distance_run(
     )
 
 
-
 @pytest.fixture()
 def dummy_run(
     dummy_datasplit,

tests/fixtures/tasks.py

@@ -28,6 +28,7 @@ def distance_task():
         tol_distance=10,
     )
 
+
 @pytest.fixture()
 def hot_distance_task():
     yield HotDistanceTaskConfig(
@@ -44,6 +45,7 @@ def hot_distance_task():
         tol_distance=10,
     )
 
+
 @pytest.fixture()
 def onehot_task():
     yield OneHotTaskConfig(