Add python_requires to setup.py (#2465)
Add python_requires to setup.py (#2465)


xray/xray,jhamman/xray,jhamman/xarray,shoyer/xarray,shoyer/xray,pydata/xarray,jhamman/xarray,markelg/xray,jhamman/xarray,pydata/xarray,chunweiyuan/xarray,markelg/xray,pydata/xarray,markelg/xray,shoyer/xarray