From b55fdcf686e29fb6db8676a53e4e378f8ccb5b84 Mon Sep 17 00:00:00 2001
From: Peter Somhorst <>
Date: Wed, 26 Aug 2026 15:06:38 +0200
Subject: [PATCH] Fix typing of cutoff frequency

---
 eitprocessing/filters/butterworth_filters.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/eitprocessing/filters/butterworth_filters.py b/eitprocessing/filters/butterworth_filters.py
index 459e2b5a9..f7a74609a 100644
--- a/eitprocessing/filters/butterworth_filters.py
+++ b/eitprocessing/filters/butterworth_filters.py
@@ -52,7 +52,7 @@ class ButterworthFilter(TimeDomainFilter):
     """
 
     filter_type: Literal["lowpass", "highpass", "bandpass", "bandstop"]
-    cutoff_frequency: float | tuple[float]
+    cutoff_frequency: float | tuple[float, float]
     order: int
     sample_frequency: float
     ignore_max_order: InitVar[bool] = False