Found a solution from importlib
test code.
Using importlib.machinery.SourceFileLoader:
>>> import importlib.machinery
>>> loader = importlib.machinery.SourceFileLoader('a_b', '/tmp/a-b.txt')
>>> mod = loader.load_module()
>>> mod
<module 'a_b' from '/tmp/a-b.txt'>
NOTE: only works in Python 3.3+.
UPDATE Loader.load_module
is deprecated since Python 3.4. Use Loader.exec_module
instead:
>>> import types
>>> import importlib.machinery
>>> loader = importlib.machinery.SourceFileLoader('a_b', '/tmp/a-b.txt')
>>> mod = types.ModuleType(loader.name)
>>> loader.exec_module(mod)
>>> mod
<module 'a_b'>
>>> import importlib.machinery
>>> import importlib.util
>>> loader = importlib.machinery.SourceFileLoader('a_b', '/tmp/a-b.txt')
>>> spec = importlib.util.spec_from_loader(loader.name, loader)
>>> mod = importlib.util.module_from_spec(spec)
>>> loader.exec_module(mod)
>>> mod
<module 'a_b' from '/tmp/a-b.txt'>