diff --git a/mne_bids_pipeline/steps/preprocessing/_04_frequency_filter.py b/mne_bids_pipeline/steps/preprocessing/_04_frequency_filter.py
index 785f9388b..8b6d7a8f8 100644
--- a/mne_bids_pipeline/steps/preprocessing/_04_frequency_filter.py
+++ b/mne_bids_pipeline/steps/preprocessing/_04_frequency_filter.py
@@ -43,6 +43,7 @@
 )
 from mne_bids_pipeline.typing import InFilesT, IntArrayT, OutFilesT, RunKindT, RunTypeT
 
+
 def get_input_fnames_frequency_filter(
     *,
     cfg: SimpleNamespace,
@@ -94,6 +95,7 @@ def zapline(
     raw = mne.io.RawArray(out.T, verbose=True, info=raw.info)
     return raw
 
+
 def notch_filter(
     raw: mne.io.BaseRaw,
     subject: str,
diff --git a/mne_bids_pipeline/tests/configs/config_eeg_matchingpennies.py b/mne_bids_pipeline/tests/configs/config_eeg_matchingpennies.py
index 77f6ac430..5d0f77614 100644
--- a/mne_bids_pipeline/tests/configs/config_eeg_matchingpennies.py
+++ b/mne_bids_pipeline/tests/configs/config_eeg_matchingpennies.py
@@ -17,4 +17,4 @@
 l_freq = None
 h_freq = 100
 zapline_fline = 50
-zapline_iter = False
\ No newline at end of file
+zapline_iter = False