ImportError: No module named _snap

[Mariatichen]

Traceback (most recent call last):
File "snap.py", line 21, in
_snap = swig_import_helper()
File "snap.py", line 20, in swig_import_helper
return importlib.import_module('_snap')
File "/usr/lib/python2.7/importlib/init.py", line 37, in import_module
import(name)