Does anybody know what kind on dog Toto fromt the Wizard of Oz was?

Cairn Terrier the offspring of a Scottish terrier! i want one they are adorable!|||In the movie a female black Cairn played Toto but people have also said Toto was a Cairn Terrier, Yorkshire Terrier and a Boston Terrier.|||A female Cairn Terrier named Terry played Toto.|||Cairn Terrier