code: def emg_features(threshold=0):
      '''Return a dictionary of popular features used for EMG time series classification.'''
      return {
          'mean_abs_value': mean_abs,
          'zero_crossings': zero_crossing(threshold),
          'slope_sign_changes': slope_sign_changes(threshold),
          'waveform_length': waveform_length,
          'integrated_emg': abs_sum,
          'emg_var': emg_var,
          'simple square integral': abs_energy,
          'root_mean_square': root_mean_square,
          'willison_amplitude': willison_amplitude(threshold),
      f emg_features(threshold=0):
      '''Return a dictionary of popular features used for EMG time series classification.'''
      return {
          'mean_abs_value': mean_abs,
          'zero_crossings': zero_crossing(threshold),
          'slope_sign_changes': slope_sign_changes(threshold),
          'waveform_length': waveform_length,
          'integrated_emg': abs_sum,
          'emg_var': emg_var,
          'simple square integral': abs_energy,
          'root_mean_square': root_mean_square,
          'willison_amplitude': willison_amplitude(threshold),
      }
docs: Return a dictionary of popular features used for EMG time series classification.