添加環境變量
C:\Python37\;
C:\Python37\Scripts;
C:\Python27\;
C:\Python27\Scripts;
運行Python2
py -2
運行Python3
py -3
運行pip2
py -2 -m pip
運行pip3
py -2 -m pip
C:\Python37\;
C:\Python37\Scripts;
C:\Python27\;
C:\Python27\Scripts;
py -2
py -3
py -2 -m pip
py -2 -m pip
class MetaCls(type): def __new__(cls, *args, **kwargs): print("in MetaCls") # return super(Meta