Context manager to allow getting an item from a dictionary and reusing

get_item_ctx_mgr.py

class get_item(object):
    def __init__(self, d, i):
        self.d = d
        self.i = i

    def __enter__(self):
        if self.i in self.d:
            return self.d[self.i]
        return None

This is a really silly context manager to avoid having to do:

if x in d:
  if isinstance(d[x], str):
    # do something with d[x]

...where x is a complex variable like "{0}/{1}/{2}".format(a, b, c) and you don't want to write it a bunch but you also don't want a local variable hanging around. So it ends up looking like:

with get_item(d, x) as myvar:
  if isinstance(myvar, str):
    # do something with myvar

... like I said, really silly. Probably too much Clojure today.

And I only pasted it here to ask if there was something like this in stdlib already that I missed. (Which I'm pretty sure there isn't because it's silly.)