this code is get the templates/blog1/page.html in b.py:
path = os.path.join(os.path.dirname(__file__), os.path.join(\'templates\', \'blog1/page.html\'))
I think use this is better:
os.path.realpath(__file__).rsplit('/', X)[0]
In [1]: __file__ = "/aParent/templates/blog1/page.html"
In [2]: os.path.realpath(__file__).rsplit('/', 3)[0]
Out[3]: '/aParent'
In [4]: __file__ = "/aParent/templates/blog1/page.html"
In [5]: os.path.realpath(__file__).rsplit('/', 1)[0]
Out[6]: '/aParent/templates/blog1'
In [7]: os.path.realpath(__file__).rsplit('/', 2)[0]
Out[8]: '/aParent/templates'
In [9]: os.path.realpath(__file__).rsplit('/', 3)[0]
Out[10]: '/aParent'