Coverity tool

[sybrandy]

>> - Use Before Test: here the bugs are in the code paths of the try-except.
>
> Not sure what this means.

If I remember correctly from when I had an opportunity to look at these 
types of tools, this is a case where, in C or C++, you have a variable 
that may be uninitialized or set to NULL, but you don't test for it 
until you have tried to use it.  I believe the root cause of this bug 
has nothing to do with the language, but with people going back into 
code they don't fully understand and trying to either A) use the 
variable and not know that the check is in there or B) they put the 
check in to "fix" a bug, but didn't put it in the correct spot.

Needless to say, with D setting variables to reasonable defaults, I 
believe this is mitigated, but not entirely prevented.