from scipy import signal import numpy as np UV = [0.1,0.3,0.5,0.7,0.9,1.0,0.8,0.6,0.4,0.2] sunburn = [0,0,0,0,0,0.2,0.6,0.9,0.9,0.9] correlation = signal.correlate(UV-np.mean(UV), sunburn - np.mean(sunburn), mode="full") lags = signal.correlation_lags(len(UV), len(sunburn), mode="full") lag = lags[np.argmax(abs(correlation))]'scipy.signal' has no attribute 'correlation_lags