new_df[key] = list(map(lambdax:2*x/n, new_df[key]))# avg time between samples# assumes uniform samplingdt = (b-a) / n#dt = (b-a).total_seconds() / n# get list of frequencies from the fft# new_df['Freq'] = fftfreq(len(self.df[key]), dt)new_df['Freq'] =rfftfreq...