This module defines a class, POP3, which encapsulates a
connection to an POP3 server and implements protocol as defined in
RFC 1725. The POP3 class supports both the minmal and
optional command sets.
This class implements the actual POP3 protocol. The connection is
created when the instance is initialized.
If port is omitted, the standard POP3 port (110) is used.
One exception is defined as an attribute of the poplib module: