[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

audio_filters/equal_loudness_filter.py

@@ -156,4 +156,4 @@ def process(self, sample: float) -> float:
         0.0
         """
         tmp = self.yulewalk_filter.process(sample)
-        return self.butterworth_filter.process(tmp)
+        return self.butterworth_filter.process(tmp)

audio_filters/iir_filter.py

@@ -109,4 +109,4 @@ def process(self, sample: float) -> float:
         self.input_history[0] = sample
         self.output_history[0] = result
 
-        return result
+        return result