code: def _get_c(cls, df, column, shifts):
          
          column_name = '{}_{}_{}'.format(column, shifts, 'c')
          shifts = abs(cls.to_int(shifts))
          df[column_name] = df[column].rolling(
              center=False, window=shifts).apply(np.count_nonzero)
docs: get the count of column in range (shifts)
  
          example: kdjj_0_le_20_c
          :param df: stock data
          :param column: column name
          :param shifts: range to count, only to previous
          :return: