code: def _get_rsv(df, n_days):
          
          n_days = int(n_days)
          column_name = 'rsv_{}'.format(n_days)
          low_min = df['low'].rolling(
              min_periods=1, window=n_days, center=False).min()
          high_max = df['high'].rolling(
              min_periods=1, window=n_days, center=False).max()
  
          cv = (df['close'] - low_min) / (high_max - low_min)
          df[column_name] = cv.fillna(0).astype('float64') * 100
docs: Calculate the RSV (Raw Stochastic Value) within N days
  
          This value is essential for calculating KDJs
          Current day is included in N
          :param df: data
          :param n_days: N days
          :return: None