def limit_roles(self):
        """
        Limit the roles being scanned.
        """
        new_roles = {}
        roles = self.options.limit.split(",")

        for key, value in self.roles.iteritems():
            for role in roles:
                role = role.strip()
                if key == role:
                    new_roles[key] = value

        self.roles = new_roles
Limit the roles being scanned.