Delete Method For most cases, methods are deleted because
their functionality is subsumed by other methods. However,
there are cases where a method is removed and no replacement
can be found. In the latter case, the migration of clients
relying on the method becomes a big problem. This is also
quite different from local API migration, as clients of local
API could run with a copy of the old library and call the deleted
method in the old library. We will discuss more on this
issue in Section V