docs: def start(name, config_file=None):
      '''
      starts a container in daemon mode
      '''
      if not exists(name):
          raise ContainerNotExists("The container (%s) does not exist!" % name)
      if name in running():
          raise ContainerAlreadyRunning('The container %s is already started!' % name)
      cmd = ['lxc-start', '-n', name, '-d']
      if config_file:
          cmd += ['-f', config_file]
      subprocess.check_call(cmd)