public boolean containsKey(String key) {
		boolean contains = values.containsKey(key);
		if (!contains && fallback != null) {
			contains = fallback.containsKey(key);
		}
		return contains;
	}
Determines if the given key can be found in this Configuration or its
fallback

@param key The key to find
@return Boolean indicating if the key exists or not
src/main/java/dev/jbang/Configuration.java