raise informative error when pydot is missing
raise informative error when pydot is missing

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