Improve promotion errors
Improve promotion errors

quantopian/datashape,llllllllll/datashape,blaze/datashape,FrancescAlted/datashape,FrancescAlted/datashape,cowlicks/datashape,blaze/datashape,ContinuumIO/datashape,llllllllll/datashape,cpcloud/datashape,aterrel/datashape,cpcloud/datashape,quantopian/datashape,ContinuumIO/datashape,markflorisson/datashape,cowlicks/datashape,aterrel/datashape,markflorisson/datashape