def get_sufficient_keys(args):
    """Determine which keys in args are sufficient.

    A sufficient key is one that is:

        1. Present within ``args``
        2. Does not have a value of ``''`` or ``None``.

    Args:
        args (dict): An args dict of string keys to serializeable values.

    Returns:
        A set of keys from ``args`` that are sufficient.
    """
    sufficient_keys = set()
    for key, value in args.items():
        if value not in ('', None):
            sufficient_keys.add(key)

    return sufficient_keys