code: def recall_series(y_true, y_score, k=None, value=True):
      
      y_true, y_score = to_float(y_true, y_score)
      top = _argsort(y_score, k)
  
      if not value:
          y_true = 1-y_true
  
      a = np.nan_to_num(y_true[top]).cumsum()
      return pd.Series(a, index=np.arange(1, len(a)+1))
docs: Returns series of length k whose i-th entry is the recall in the top i