@API(status = API.Status.STABLE)
    public boolean hasFlag(
            final @NonNull String name
    ) {
        return this.getValue(name).isPresent();
    }
Check whether a flag is present. This will return {@code true} if the flag
is a presence flag and is present, or if the flag is a value flag and has
a value provided.

@param name Flag name
@return whether the flag is present
cloud-core/src/main/java/org/incendo/cloud/parser/flag/FlagContext.java