diff --git a/pytorch_lightning/callbacks/model_checkpoint.py b/pytorch_lightning/callbacks/model_checkpoint.py
index 26d48c8b03e6f0..7190fccfa88dec 100644
--- a/pytorch_lightning/callbacks/model_checkpoint.py
+++ b/pytorch_lightning/callbacks/model_checkpoint.py
@@ -238,9 +238,9 @@ def on_load_checkpoint(self, callback_state: Dict[str, Any]):
 
     def _should_skip_saving_checkpoint(self, trainer) -> bool:
         return (
-            trainer.fast_dev_run # disable checkpointing with fast_dev_run
+            trainer.fast_dev_run  # disable checkpointing with fast_dev_run
             or trainer.running_sanity_check  # don't save anything during sanity check
-            or self.save_top_k == 0 # no models are saved
+            or self.save_top_k == 0  # no models are saved
             or self._last_global_step_saved == global_step  # already saved at the last step
         )
 
@@ -282,9 +282,13 @@ def __validate_init_configuration(self):
         if self.save_top_k is not None and self.save_top_k < -1:
             raise MisconfigurationException(f'Invalid value for save_top_k={self.save_top_k}. Must be None or >= -1')
         if self.every_n_epochs == 0 or self.every_n_epochs < -1:
-            raise MisconfigurationException(f'Invalid value for every_n_epochs={self.every_n_epochs}. Must be positive or -1')
+            raise MisconfigurationException(
+                f'Invalid value for every_n_epochs={self.every_n_epochs}. Must be positive or -1'
+            )
         if self.every_n_batches == 0 or self.every_n_batches < -1:
-            raise MisconfigurationException(f'Invalid value for every_n_batches={self.every_n_batches}. Must be positive or -1')
+            raise MisconfigurationException(
+                f'Invalid value for every_n_batches={self.every_n_batches}. Must be positive or -1'
+            )
         if self.monitor is None:
             # None: save last epoch, -1: save all epochs, 0: nothing is saved
             if self.save_top_k not in [None, -1, 0]:
diff --git a/tests/checkpointing/test_model_checkpoint.py b/tests/checkpointing/test_model_checkpoint.py
index aacb5b73c64bce..bb7f4df8e3d707 100644
--- a/tests/checkpointing/test_model_checkpoint.py
+++ b/tests/checkpointing/test_model_checkpoint.py
@@ -499,21 +499,19 @@ def test_none_monitor_top_k(tmpdir):
     ModelCheckpoint(dirpath=tmpdir, save_top_k=-1)
     ModelCheckpoint(dirpath=tmpdir, save_top_k=0)
 
+
 def test_invalid_every_n_epoch(tmpdir):
     """ Test that an exception is raised for every_n_epochs = 0 or < -1. """
-    with pytest.raises(
-        MisconfigurationException, match=r'Invalid value for every_n_epochs=0*'
-    ):
+    with pytest.raises(MisconfigurationException, match=r'Invalid value for every_n_epochs=0*'):
         ModelCheckpoint(dirpath=tmpdir, every_n_epochs=0)
-    with pytest.raises(
-        MisconfigurationException, match=r'Invalid value for every_n_epochs=-2*'
-    ):
+    with pytest.raises(MisconfigurationException, match=r'Invalid value for every_n_epochs=-2*'):
         ModelCheckpoint(dirpath=tmpdir, every_n_epochs=-2)
 
     # These should not fail
     ModelCheckpoint(dirpath=tmpdir, every_n_epochs=-1)
     ModelCheckpoint(dirpath=tmpdir, every_n_epochs=3)
 
+
 def test_invalid_every_n_batches(tmpdir):
     """ Test that an exception is raised for every_n_batches = 0 or < -1. """
     with pytest.raises(MisconfigurationException, match=r'Invalid value for every_n_batches=0*'):