@Override
	public boolean hasHistory(@Nonnull String key) {
		// History implies there are past entries for the current value, hence more than one entry.
		Stack<I> stack = history.get(key);
		return stack != null && stack.size() > 1;
	}
History contains a stack of prior states of items.
If an item has not been modified there is no entry in this map.

@return Map of historical states of items within this bundle.
recaf-core/src/main/java/software/coley/recaf/workspace/model/bundle/BasicBundle.java