After I upgraded to Portage-2.1-pre1,i can't emerge anything

[Greyhound]

Help me, thanks,
the error is :

Allen bin # emerge


!!! Failed to complete python imports. There are internal modules for
!!! python and failure here indicates that you have a problem with python
!!! itself and thus portage is not able to continue processing.

!!! You might consider starting python with verbose flags to see what has
!!! gone wrong. Here is the information we got for this exception:
No module named cache.cache_errors

[amne]

Moved from Portage & Programming to Duplicate Threads.

See portage-2.1_pre1 python module problem for a solution.
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