Signal processing(signal.sosfilt) won't work using recording_queue.py #1

Data from my_queue.to_array() can be plotted with plt.plot. However, signal processing routine won't work.
Can you help me?

plt.figure(figsize=(10,6))
plt.subplot(3,1,1)
plt.plot(my_queue.to_array())

sos_rr = signal.butter(4, 0.4, 'lowpass', fs=int(1000), output='sos')
sos_hr= signal.butter(4, [0.8,2.5], 'bp', fs=int(1000),output='sos')

filtered_hr = signal.sosfilt(sos_hr, data1[0:20000])
filtered_rr = signal.sosfilt(sos_hr, my_queue.to_array())

plt.subplot(3,1,2)
plt.plot(filtered_hr)
plt.subplot(3,1,3)
plt.plot(filtered_rr)
plt.show()

Every thing works OK except signal process routine...