Provide an error message when raising NonConvertibleData
Provide an error message when raising NonConvertibleData

dbirchak/cartodb,DigitalCoder/cartodb,CartoDB/cartodb,codeandtheory/cartodb,codeandtheory/cartodb,future-analytics/cartodb,bloomberg/cartodb,UCL-ShippingGroup/cartodb-1,DigitalCoder/cartodb,future-analytics/cartodb,nyimbi/cartodb,UCL-ShippingGroup/cartodb-1,codeandtheory/cartodb,DigitalCoder/cartodb,thorncp/cartodb,future-analytics/cartodb,DigitalCoder/cartodb,thorncp/cartodb,thorncp/cartodb,dbirchak/cartodb,bloomberg/cartodb,dbirchak/cartodb,UCL-ShippingGroup/cartodb-1,splashblot/dronedb,CartoDB/cartodb,UCL-ShippingGroup/cartodb-1,nuxcode/cartodb,nuxcode/cartodb,future-analytics/cartodb,raquel-ucl/cartodb,codeandtheory/cartodb,bloomberg/cartodb,thorncp/cartodb,nyimbi/cartodb,nuxcode/cartodb,nuxcode/cartodb,raquel-ucl/cartodb,splashblot/dronedb,dbirchak/cartodb,codeandtheory/cartodb,nyimbi/cartodb,dbirchak/cartodb,splashblot/dronedb,DigitalCoder/cartodb,raquel-ucl/cartodb,nuxcode/cartodb,CartoDB/cartodb,raquel-ucl/cartodb,nyimbi/cartodb,splashblot/dronedb,CartoDB/cartodb,splashblot/dronedb,UCL-ShippingGroup/cartodb-1,raquel-ucl/cartodb,nyimbi/cartodb,bloomberg/cartodb,CartoDB/cartodb,future-analytics/cartodb,thorncp/cartodb,bloomberg/cartodb