avoid empty dataframe(dtype=...) error
avoid empty dataframe(dtype=...) error

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