code: def _cumulative_gain_curve(y_true, y_score, pos_label=None):
      """
      This method is copied from scikit-plot package.
      See https://github.com/reiinakano/scikit-plot/blob/2dd3e6a76df77edcbd724c4db25575f70abb57cb/scikitplot/helpers.py#L157
  
      This function generates the points necessary to plot the Cumulative Gain
  
      Note: This implementation is restricted to the binary classification task.
  
      Args:
          y_true (array-like, shape (n_samples)): True labels of the data.
  
          y_score (array-like, shape (n_samples)): Target scores, can either be
              probability estimates of the positive class, confidence values, or
              non-thresholded measure of decisions (as returned by
              decision_function on some classifiers).
  
          pos_label (int or str, default=None): Label considered as positive and
              others are considered negative
  
      Returns:
          percentages (numpy.ndarray): An array containing the X-axis values for
              plotting the Cumulative Gains chart.
  
          gains (numpy.ndarray): An array containing the Y-axis values for one
              curve of the Cumulative Gains chart.
  
      Raises:
          ValueError: If `y_true` is not composed of 2 classes. The Cumulative
              Gain Chart is only relevant in binary classification.
      """
      y_true, y_score = np.asarray(y_true), np.asarray(y_score)
  
      # ensure binary classification if pos_label is not specified
      classes = np.unique(y_true)
      if pos_label is None and not (
          np.array_equal(classes, [0, 1])
          or np.array_equal(classes, [-1, 1])
          or np.array_equal(classes, [0])
          or np.array_equal(classes, [-1])
          or np.array_equal(classes, [1])
      ):
          raise ValueError(
              "Data is not binary and pos_label is not specified"
          )
      elif pos_label is None:
          pos_label = 1.0
  
      # make y_true a boolean vector
      y_true = y_true == pos_label
  
      sorted_indices = np.argsort(y_score)[::-1]
      y_true = y_true[sorted_indices]
      gains = np.cumsum(y_true)
  
      percentages = np.arange(start=1, stop=len(y_true) + 1)
  
      gains = gains / float(np.sum(y_true))
      percentages = percentages / float(len(y_true))
  
      gains = np.insert(gains, 0, [0])
      percentages = np.insert(percentages, 0, [0])
  
      return percentages, gains
  
imports: import matplotlib.pyplot
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: _cumulative_gain_curve(y_true, y_score, pos_label) and returns: percentages,  gains