forcibly clean out _sessions, _mapper_registry at test start to eliminate leftovers from other unit tests (from other test scripts) still stored in memory
forcibly clean out _sessions, _mapper_registry at test start to eliminate leftovers from other unit tests (from other test scripts) still stored in memory

graingert/sqlalchemy,wujuguang/sqlalchemy,olemis/sqlalchemy,276361270/sqlalchemy,bdupharm/sqlalchemy,bootandy/sqlalchemy,Cito/sqlalchemy,EvaSDK/sqlalchemy,graingert/sqlalchemy,monetate/sqlalchemy,pdufour/sqlalchemy,davidfraser/sqlalchemy,inspirehep/sqlalchemy,pdufour/sqlalchemy,bootandy/sqlalchemy,wujuguang/sqlalchemy,WinterNis/sqlalchemy,dstufft/sqlalchemy,elelianghh/sqlalchemy,WinterNis/sqlalchemy,hsum/sqlalchemy,sqlalchemy/sqlalchemy,alex/sqlalchemy,olemis/sqlalchemy,robin900/sqlalchemy,sandan/sqlalchemy,brianv0/sqlalchemy,halfcrazy/sqlalchemy,Akrog/sqlalchemy,davidjb/sqlalchemy,inspirehep/sqlalchemy,bdupharm/sqlalchemy,Cito/sqlalchemy,ThiefMaster/sqlalchemy,alex/sqlalchemy,sandan/sqlalchemy,elelianghh/sqlalchemy,ThiefMaster/sqlalchemy,epa/sqlalchemy,robin900/sqlalchemy,alex/sqlalchemy,brianv0/sqlalchemy,dstufft/sqlalchemy,j5int/sqlalchemy,zzzeek/sqlalchemy,j5int/sqlalchemy,davidfraser/sqlalchemy,itkovian/sqlalchemy,itkovian/sqlalchemy,wfxiang08/sqlalchemy,hsum/sqlalchemy,halfcrazy/sqlalchemy,EvaSDK/sqlalchemy,Akrog/sqlalchemy,epa/sqlalchemy,wfxiang08/sqlalchemy,276361270/sqlalchemy,monetate/sqlalchemy,davidjb/sqlalchemy,Cito/sqlalchemy