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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _build_command(self, cmds, sync=False):
 """Build full EOS's openstack CLI command. Helper method to add commands to enter and exit from openstack CLI modes. :param cmds: The openstack CLI commands that need to be executed in the openstack config mode. :param sync: This flags indicates that the region is being synced. """


        region_cmd = 'region %s' % self.region
        if sync:
            region_cmd = self.cli_commands[const.CMD_REGION_SYNC]

        full_command = [
            'enable',
            'configure',
            'cvx',
            'service openstack',
            region_cmd,
        ]
        full_command.extend(cmds)
        return full_command