iotable_get for the source naio_10_cp1750 is not working

[IwoA]

iotable_get(source = "naio_10_cp1750", geo = "SK") throws misleading error "This currency unit is not found in the raw data frame."

The error should be like "This country is not found in the raw data frame." or like it is for Denmark "There is no available table for country DK in the year 1990 with MIO_EUR units."

By the way this function should check the tempfile before downloading the same data again as it is done in the eurostat package.