def has_role(self, role_s):
if self.authorized:<EOL><INDENT>return self.security_manager.has_role(self.identifiers, role_s)<EOL><DEDENT>msg = '<STR_LIT>'<EOL>raise ValueError(msg)<EOL>
:param role_s: 1..N role identifiers (strings)
:type role_s:  Set of Strings

:returns: a set of tuple(s), containing the role and a Boolean
          indicating whether the user is a member of the Role