returns the necessary string value for an HKEY for the win32security module

def getSecurityHkey(self, s):
        '''
        returns the necessary string value for an HKEY for the win32security module
        '''
        try:
            return self.hkeys_security[s]
        except KeyError:
            raise CommandExecutionError((
                'No HKEY named "{0}".  It should be one of the following:  {1}'
                ).format(s, ', '.join(self.hkeys_security)))