code: def new_feature(signal):
      """Computes a new feature
      Parameters
      ----------
      signal : nd-array
          Input from which new feature is computed
  
      Returns
      -------
      float
          new feature
      """
      return np.mean(signal) - np.std(signal)
  
imports: from tsfel.feature_extraction.features_utils import set_domain
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: new_feature(signal) and returns: unknown