code: def QA_indicator_BOLL(DataFrame, N=20, P=2):
      '布林线'
      C = DataFrame['close']
      boll = MA(C, N)
      UB = boll + P * STD(C, N)
      LB = boll - P * STD(C, N)
      DICT = {'BOLL': boll, 'UB': UB, 'LB': LB}
  
      return pd.DataFrame(DICTf QA_indicator_BOLL(DataFrame, N=20, P=2):
      '布林线'
      C = DataFrame['close']
      boll = MA(C, N)
      UB = boll + P * STD(C, N)
      LB = boll - P * STD(C, N)
      DICT = {'BOLL': boll, 'UB': UB, 'LB': LB}
  
      return pd.DataFrame(DICT)
docs: 布林线