def __enter__(self):
self.pushDefaultContext(self)<EOL>return self<EOL>
Creates a scope where this context is default, so all calls made while it is in scope will begin with
the default context information.

:usage      |import orb
            |with orb.Context(database=db):
            |   user = models.User()
            |   group = models.Group()

:return:  <orb.Context>