def _getRole(self, matchedVars):
        """
        :param matchedVars:
        :return: NULL or the role's integer value
        """
        role = matchedVars.get(ROLE)
        if role is not None and role.strip() == '':
            role = NULL
        else:
            valid = Authoriser.isValidRoleName(role)
            if valid:
                role = Authoriser.getRoleFromName(role)
            else:
                self.print("Invalid role. Valid roles are: {}".
                           format(", ".join(map(lambda r: r.name, Roles))),
                           Token.Error)
                return False
        return role