ExceptionContext : adding context to exceptions with "with" statement

ExceptionContext.py

from contextlib import AbstractContextManager
from future.utils import raise_from


class ExceptionContext(AbstractContextManager) :
    def __init__(self, context):
        self.context = context

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_val != None :
            raise_from(Exception("Context : %s" % str(self.context)), exc_val)
        return True