PackagesNotFoundError: The following packages are not available from current channels python=2.7
新版本conda(4.12以上的版本)创建python2.x的环境时,会提示找不到包.报错Collectingpackagemetadata(current_repodata.json):doneSolvingenvironment:failedwithrepodatafromcurrent_repodata.json,willretrywithnextrepodatasource.Collect