-# Used to indicate that an account does not exist on the filesystem.
-class NonexistentAccountError < StandardError
-end
-
-
-# Used to indicate that a domain does not exist on the filesystem.
-class NonexistentDomainError < StandardError
-end
+# An error indicating that some user already exists. For example, if
+# one tries to rename a user and the destination user already exists.
+class UserAlreadyExistsError < StandardError; end