- this collection can be None on cleanup, so check for that
- this collection can be None on cleanup, so check for that

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