Throw an exception when a NULL pipeline is given
Throw an exception when a NULL pipeline is given

Kitware/sprokit,linus-sherrill/sprokit,Kitware/sprokit,linus-sherrill/sprokit,linus-sherrill/sprokit,mathstuf/sprokit,linus-sherrill/sprokit,Kitware/sprokit,Kitware/sprokit,mathstuf/sprokit,mathstuf/sprokit,mathstuf/sprokit