code: def ecdf_slope(signal, p_init=0.5, p_end=0.75):
      """Computes the slope of the ECDF between two percentiles.
      Possibility to return infinity values.
  
      Feature computational cost: 1
  
      Parameters
      ----------
      signal : nd-array
          Input from which ECDF is computed
      p_init : float
          Initial percentile
      p_end : float
          End percentile
  
      Returns
      -------
      float
          The slope of the ECDF between two percentiles
      """
      signal = np.array(signal)
      # check if signal is constant
      if np.sum(np.diff(signal)) == 0:
          return np.inf
      else:
          x_init, x_end = ecdf_percentile(
              signal, percentile=[p_init, p_end]
          )
          return (p_end - p_init) / (x_end - x_init)
  
imports: import scipy.signal
  from tsfel.feature_extraction.features_utils import *
label_desc: Use image node_id 33 for calling a global function with example usage: ecdf_slope(signal, p_init, p_end) and returns: np, unknown