import imp
import importlib
import sys
dirname = r'c:\Python33\dlls'

name = '_bz2'
assert name not in sys.modules

use_imp = True
if use_imp:
    fp, pathname, description = imp.find_module(name, [dirname])
    mod = imp.load_module(name, fp, pathname, description)
else:
    loader = importlib.machinery.PathFinder.find_module(name, [dirname])
    mod = loader.load_module(name)
print (mod)