public static <T> Collection<T> asCollection(Collection<T> c) {
		if (c == null) {
			return new HashSet<>();
		}
		return c;
	}
Returns the given collection if not null, an empty collection otherwise.  This is
useful for clients avoid null checks.

@param c the collection to check
@return a non-null collection
Ghidra/Framework/Generic/src/main/java/util/CollectionUtils.java