Naming convention for context-manager classes ("with" blocks)

Question

Is there a general naming convention for classes or functions that are meant to be used in with block such as

with CreateSomeContext() as x:
    ...

? Something that signals that the class or the result of a function should be used with with?

Answer 1

In the respective PEP 0343, there is a mention of two conventions:

The tense used in the names of the example contexts is not arbitrary. Past tense ("-ed") is used when the name refers to an action which is done in the __enter__ method and undone in the __exit__ method. Progressive tense ("-ing") is used when the name refers to an action which is to be done in the __exit__ method.

Answer 2

There's no naming convention (open, socket.create_connection, urllib.request.urlopen all return context managers which can be used with with) but context managers will have the __enter__ and __exit__ methods.

Note: in the case of open("file", "w"), the return value (the file object) is the context manager, not open.