* Merges a piece of data with the existing data at a specified path. Any pre-existing data
* which is not explicitly overwritten will be preserved. This means that if you store a container,
* its child lists will be merged.
* Merges a piece of data with the existing data at a specified path. Any pre-existing data
* which is not explicitly overwritten will be preserved. This means that if you store a container,
* its child lists will be merged.