import sys,types,os; p = os.path.join(sys._getframe(1).f_locals['sitedir'], *('p1',)); ie = os.path.exists(os.path.join(p,'__init__.py')); m = not ie and sys.modules.setdefault('p1',types.ModuleType('p1')); mp = (m or []) and m.__dict__.setdefault('__path__',[]); (p not in mp) and mp.append(p)