hierarchyLevel casts a level into a level. Used to resolve ambiguity resulting from function signatures with the same name. For example, assume that you have two function signatures, and one takes a level and the other takes a hierarchy. If the name of the level and the hierarchy are the same, then invoking that function in a formula creates ambiguity. By explicitly casting the string with the hierarchyLevel function, the ambiguity is resolved.
hierarchyLevel(levelObj)