diff --git a/tools/ecg2wav.py b/tools/ecg2wav.py
index 8ee55c0657fb73075366efe2a1b0826c079681a9..98843e42daa36264002aea5db2b1d0db75a47472 100644
--- a/tools/ecg2wav.py
+++ b/tools/ecg2wav.py
@@ -4,6 +4,7 @@ import wave
 import sys
 import struct
 
+
 def read(file_name):
     signal = numpy.fromfile(file_name, dtype=numpy.int16)
     return signal
@@ -12,19 +13,18 @@ def read(file_name):
 signal = read(sys.argv[1])
 
 
-sampleRate = 128.0   # hertz
-duration = len(signal) / sampleRate   # seconds
+sampleRate = 128.0  # hertz
+duration = len(signal) / sampleRate  # seconds
 
-wavef = wave.open('out.wav','w')
-wavef.setnchannels(1) # mono
-wavef.setsampwidth(2) 
+wavef = wave.open("out.wav", "w")
+wavef.setnchannels(1)  # mono
+wavef.setsampwidth(2)
 wavef.setframerate(sampleRate)
 
 for i in range(int(duration * sampleRate)):
     value = int(signal[i])
-    data = struct.pack('<h', value)
-    wavef.writeframesraw( data )
+    data = struct.pack("<h", value)
+    wavef.writeframesraw(data)
 
 
 wavef.close()
-