(Keeping mutables safe) Suggest a simple scheme for creating a new class SafeMember that would allow us to export a reference to a Member. The classes outside the system should be unaware of this...

 (Keeping mutables safe) Suggest a simple scheme for creating a new class
SafeMember that would allow us to export a reference to a Member. The
classes outside the system should be unaware of this additional class, and access
the reference like a reference to a Member object. However, the reference would
not allow the integrity of the data to be compromised.