[Bug/Feature Request] When mapping to a class with fields which are not belonging to same class, error occurs.

[jinskjoy]

Say class A has a field called field1 which is instance of class B.
Class C has field1 which is instance of class D
Mapping directly from A->D is failing unless we register mapping from B->D

class B:
pass
class A:
field1: B
class D:
pass
class C:
field1: D

mapper.to(C).map(A()) - fails

mapper.add(B,D)
mapper.to(C).map(A()) - now succeeds

Example fiddle : https://python-fiddle.com/saved/8999c303-a806-417c-9bdd-d3f3f5206513

It would be great if the mapper automatically handle this.