check extensions each time; user-defined code will be appending to "extensions" after the AttributeImpl has been constructed
check extensions each time; user-defined code will be appending to "extensions" after the AttributeImpl has been constructed

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