== Why is this an issue?

Calling the ``++not++`` or ``++~++`` prefix operator twice might be redundant: the second invocation undoes the first. Such mistakes are typically caused by accidentally double-tapping the key in question without noticing. Either this is a bug, if the operator was actually meant to be called once, or misleading if done on purpose.
Calling ``++not++`` twice is commonly done instead of using the dedicated "bool()" builtin function. However, the latter one increases the code readability and should be used.

=== Noncompliant code example

[source,python]
----
a = 0
b = False

c = not not a # Noncompliant
d = ~~b # Noncompliant
----

=== Compliant solution

[source,python]
----
a = 0
b = False

c = bool(a)
d = ~b
----

=== Exceptions

If the ``++~++`` function has been overloaded in a customised class and has been called twice, no warning is raised as it is assumed to be an expected usage.

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Use the "{not|~}" operator just once or not at all.

Use the "bool()" builtin function instead of calling "not" twice.

'''
== Comments And Links
(visible only on this page)

include::../comments-and-links.adoc[]
endif::env-github,rspecator-view[]