ValueError: Of the four parameters: start, end, periods, and freq, exactly three must be specified

错误写法：

print(pd.date_range(start='20201001',end='20201203',periods=5,freq='2D'))

start，end，periods，freq这4个参数只能设置3个，否则会报错

pandas中源码如下：

 if com.count_not_none(start, end, periods, freq) != 3:
           raise ValueError(
               "Of the four parameters: start, end, periods, "
               "and freq, exactly three must be specified"
           )