The poplib module provides two classes, not one.

Doc/library/poplib.rst

@@ -24,7 +24,7 @@ quality of POP3 servers varies widely, and too many are quite poor. If your
 mailserver supports IMAP, you would be better off using the
 :class:`imaplib.IMAP4` class, as IMAP servers tend to be better implemented.
 
-A single class is provided by the :mod:`poplib` module:
+The :mod:`poplib` module provides two classes:
 
 
 .. class:: POP3(host, port=POP3_PORT[, timeout])