[Tutor] properly propagate problems

[ingo janssen]

On 24/03/2019 00:03, Cameron Simpson wrote:
> Short takeaway: decide what's mechanism and what is policy, and try to 
> put policy further out in higher level code.

That, Cameron, was a very insightful answer and an eye opener, as I try 
to 'fix things' as early as possible. It also answered the question that 
I thought of right after posting, what if it is a library and knows 
nothing about its use? I'll certainty have a look at Pfx.

Thank you Cameron,

ingo