code: def _get_dmi(cls, df):
          
          df['pdi'] = cls._get_pdi(df, 14)
          df['mdi'] = cls._get_mdi(df, 14)
          df['dx'] = cls._get_dx(df, 14)
          df['adx'] = df['dx_6_ema']
          df['adxr'] = df['adx_6_ema']
docs: get the default setting for DMI
  
          including:
          +DI: 14 days SMMA of +DM,
          -DI: 14 days SMMA of -DM,
          DX: based on +DI and -DI
          ADX: 6 days SMMA of DX
          :param df: data
          :return: