code: def hudgins_features(threshold=0):
      """Return a dict of Hudgin's time domain 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,
      }
  
imports: import numpy
  from scipy import stats
label_desc: Use image node_id 3 for calling a global function with example usage: hudgins_features(threshold) and returns: dict