diff --git a/km3io/online.py b/km3io/online.py
index 79e2833b71359fa53352d7d8655177a31dad62f3..20c2dccc11eadb2677f7cab3f9de97aea5f721b9 100644
--- a/km3io/online.py
+++ b/km3io/online.py
@@ -336,7 +336,7 @@ class OnlineEvents:
 
     def __getitem__(self, item):
         return OnlineEvent(self.headers[item], self.snapshot_hits[item],
-                        self.triggered_hits[item])
+                           self.triggered_hits[item])
 
     def __len__(self):
         return len(self.headers)
diff --git a/km3io/tools.py b/km3io/tools.py
index 478faad65f078f5b2c77eceb902381f2d7b82240..5448d61bf092407e186c5dccb0184b0a8c499ae9 100644
--- a/km3io/tools.py
+++ b/km3io/tools.py
@@ -36,17 +36,16 @@ def _unfold_indices(obj, indices):
 
 
 class BranchMapper:
-    def __init__(
-            self,
-            name,
-            key,
-            extra=None,
-            exclude=None,
-            update=None,
-            attrparser=None,
-            flat=True,
-            interpretations=None,
-            toawkward=None):
+    def __init__(self,
+                 name,
+                 key,
+                 extra=None,
+                 exclude=None,
+                 update=None,
+                 attrparser=None,
+                 flat=True,
+                 interpretations=None,
+                 toawkward=None):
         """
         Mapper helper for keys in a ROOT branch.
 
@@ -191,8 +190,8 @@ class Branch:
     def __str__(self):
         length = len(self)
         return "{} ({}) with {} element{}".format(self.__class__.__name__,
-                                               self._mapper.name, length,
-                                               's' if length > 1 else '')
+                                                  self._mapper.name, length,
+                                                  's' if length > 1 else '')
 
     def __repr__(self):
         length = len(self)
diff --git a/tests/test_gseagen.py b/tests/test_gseagen.py
index ea412a04cfd6de1e85dda88b246abe0e6cd6279b..8a2c9bdb946dcb8636425b42408d83885ea7bd09 100644
--- a/tests/test_gseagen.py
+++ b/tests/test_gseagen.py
@@ -47,7 +47,7 @@ class TestGSGHeader(unittest.TestCase):
         self.assertAlmostEqual(self.header["SiteLatitude"], 0.747)
         self.assertAlmostEqual(self.header["SiteLongitude"], 0.10763)
         self.assertAlmostEqual(self.header["SeaBottomRadius"], 6368000.)
-        assert round(self.header["GlobalGenWeight"]-6.26910765e+08, 0) == 0
+        assert round(self.header["GlobalGenWeight"] - 6.26910765e+08, 0) == 0
         self.assertAlmostEqual(self.header["RhoSW"], 1.03975)
         self.assertAlmostEqual(self.header["RhoSR"], 2.65)
         self.assertAlmostEqual(self.header["TGen"], 31556926.)
diff --git a/tests/test_online.py b/tests/test_online.py
index 72bb4e51b8fb72b533da26f1d0ed14b08e9ab5dc..35364205d7dd3aad375357d25e8ec4c7e6d825c1 100644
--- a/tests/test_online.py
+++ b/tests/test_online.py
@@ -10,7 +10,7 @@ SAMPLES_DIR = os.path.join(os.path.dirname(__file__), "samples")
 class TestOnlineEvents(unittest.TestCase):
     def setUp(self):
         self.events = OnlineReader(os.path.join(SAMPLES_DIR,
-                                             "daq_v1.0.0.root")).events
+                                                "daq_v1.0.0.root")).events
 
     def test_index_lookup(self):
         assert 3 == len(self.events)
@@ -25,7 +25,7 @@ class TestOnlineEvents(unittest.TestCase):
 class TestOnlineEvent(unittest.TestCase):
     def setUp(self):
         self.event = OnlineReader(os.path.join(SAMPLES_DIR,
-                                            "daq_v1.0.0.root")).events[0]
+                                               "daq_v1.0.0.root")).events[0]
 
     def test_str(self):
         assert re.match(".*event.*96.*snapshot.*18.*triggered",
@@ -39,7 +39,7 @@ class TestOnlineEvent(unittest.TestCase):
 class TestOnlineEventsSnapshotHits(unittest.TestCase):
     def setUp(self):
         self.events = OnlineReader(os.path.join(SAMPLES_DIR,
-                                             "daq_v1.0.0.root")).events
+                                                "daq_v1.0.0.root")).events
         self.lengths = {0: 96, 1: 124, -1: 78}
         self.total_item_count = 298
 
@@ -78,7 +78,7 @@ class TestOnlineEventsSnapshotHits(unittest.TestCase):
 class TestOnlineEventsTriggeredHits(unittest.TestCase):
     def setUp(self):
         self.events = OnlineReader(os.path.join(SAMPLES_DIR,
-                                             "daq_v1.0.0.root")).events
+                                                "daq_v1.0.0.root")).events
         self.lengths = {0: 18, 1: 53, -1: 9}
         self.total_item_count = 80
 
@@ -119,7 +119,7 @@ class TestOnlineEventsTriggeredHits(unittest.TestCase):
 class TestTimeslices(unittest.TestCase):
     def setUp(self):
         self.ts = OnlineReader(os.path.join(SAMPLES_DIR,
-                                         "daq_v1.0.0.root")).timeslices
+                                            "daq_v1.0.0.root")).timeslices
 
     def test_data_lengths(self):
         assert 3 == len(self.ts._timeslices["L1"][0])
@@ -145,7 +145,7 @@ class TestTimeslices(unittest.TestCase):
 class TestTimeslice(unittest.TestCase):
     def setUp(self):
         self.ts = OnlineReader(os.path.join(SAMPLES_DIR,
-                                         "daq_v1.0.0.root")).timeslices
+                                            "daq_v1.0.0.root")).timeslices
         self.n_frames = {"L1": [69, 69, 69], "SN": [64, 66, 68]}
 
     def test_str(self):
@@ -159,7 +159,7 @@ class TestTimeslice(unittest.TestCase):
 class TestSummaryslices(unittest.TestCase):
     def setUp(self):
         self.ss = OnlineReader(os.path.join(SAMPLES_DIR,
-                                         "daq_v1.0.0.root")).summaryslices
+                                            "daq_v1.0.0.root")).summaryslices
 
     def test_headers(self):
         assert 3 == len(self.ss.headers)