text: class WWSHCError(BaseException): pass
  class WWSHCNotExistingError(WWSHCError): pass
  class NoSuchGroup(WWSHCNotExistingError): pass
  class NoSuchClass(WWSHCNotExistingError): pass
  class NoSuchUser(WWSHCNotExistingError): pass
  class AlreadyInContacts(WWSHCError): pass
  