Hello, Here is a documentation bug report, per https://docs.python.org/3/bugs.html#documentation-bugs Suggest "is" -> "if" in Doc/library/contextvars.rst. Patch follows. =================================================================== --- Doc/library/contextvars.rst (revision c3dd7e45cc5d36bbe2295c2840faabb5c75d83e4) +++ Doc/library/contextvars.rst (date 1597766187592) @@ -110,7 +110,7 @@ A read-only property. Set to the value the variable had before the :meth:`ContextVar.set` method call that created the token. - It points to :attr:`Token.MISSING` is the variable was not set + It points to :attr:`Token.MISSING` if the variable was not set before the call. .. attribute:: Token.MISSING