How to change the "collecting pip source"

I an in China,and I want to snap a python application, but here sth was wrong. Whenever I try the “snapcraft” command ,a collection pip timeout error will always occur.I think it is because of the geographical location that I can not use the foreign data source,so here I would like to ask if I can change the source of the plugin download to slove this error. Following is the picture about what I have meeted.