def exists(args, key):
    if key in args:
        return args[key]
    else:
        raise ArgumentError(_('Argument %s is required.') % key)
Validates that a freeform string argument to a RPC method call is given.
dataset/ETHPy150Open nii-cloud/dodai-compute/plugins/xenserver/xenapi/etc/xapi.d/plugins/pluginlib_nova.py/exists