code: def zero_cross(signal):
      """Computes Zero-crossing rate of the signal.
  
      Corresponds to the total number of times that the signal changes from
      positive to negative or vice versa.
  
      Feature computational cost: 1
  
      Parameters
      ----------
      signal : nd-array
          Input from which the zero-crossing rate are computed
  
      Returns
      -------
      int
          Number of times that signal value cross the zero axis
  
      """
      return len(np.where(np.diff(np.sign(signal)))[0])
  
imports: import scipy.signal
  from tsfel.feature_extraction.features_utils import *
label_desc: Use image node_id 11 for calling a global function with example usage: zero_cross(signal) and returns: len