code: def _get_r(cls, df, column, shifts):
          
          shift = cls.to_int(shifts)
          rate_key = '{}_{}_r'.format(column, shift)
          df[rate_key] = df[column].pct_change(periods=-shift) * 100
docs: Get rate of change of column
  
          :param df: DataFrame object
          :param column: column name of the rate to calculate
          :param shifts: days to shift, accept one shift only
          :return: None