def _global_params(self_update, snapshot=None, quiet=False):
    """Utility function to prepare common global parameters."""
    params = ["--non-interactive", "--drop-if-no-change"]
    if self_update is False:
        params.append("--no-selfupdate")
    if snapshot and snapshot != "continue":
        params.extend(["--continue", snapshot])
    elif snapshot:
        params.append("--continue")
    if quiet:
        params.append("--quiet")
    return params