type check a bit in join
type check a bit in join

simudream/dask,jakirkham/dask,hainm/dask,ssanderson/dask,blaze/dask,freeman-lab/dask,esc/dask,dask/dask,pombredanne/dask,PhE/dask,jcrist/dask,mraspaud/dask,hainm/dask,clarkfitzg/dask,cpcloud/dask,minrk/dask,jakirkham/dask,ssanderson/dask,jayhetee/dask,mikegraham/dask,wiso/dask,marianotepper/dask,simudream/dask,jcrist/dask,cowlicks/dask,blaze/dask,mrocklin/dask,clarkfitzg/dask,minrk/dask,jayhetee/dask,mrocklin/dask,PhE/dask,ContinuumIO/dask,chrisbarber/dask,ContinuumIO/dask,esc/dask,pombredanne/dask,dask/dask,gameduell/dask,wiso/dask,vikhyat/dask,freeman-lab/dask,PeterDSteinberg/dask,mraspaud/dask,vikhyat/dask,marianotepper/dask