GeezerVison

The membership-test description currently reads like a direct instance lookup of contains, which can differ from the lookup used by in.

Describe the implicit call and link to the existing special-method lookup section. This avoids presenting either an instance call or an ordinary type attribute lookup as an exact equivalent.

Validation: the reported instance-override example and a metaclass lookup example both confirm the distinction on Python 3.14.7. Sphinx lint passes for the edited file, and the cross-reference target exists. A full documentation build has not been run due to local artifact storage limits.

• Issue: A minor problem with the section "6.10.2. Membership test operations" from the language reference. #159034