Fix for issue #265. Ensure the passed object has a callable listen() method. This test should pass for socket.socket and socket._socket objects. Otherwise treat it as an address/port tuple (the old behavior).
Fix for issue #265. Ensure the passed object has a callable listen() method. This test should pass for socket.socket and socket._socket objects. Otherwise treat it as an address/port tuple (the old behavior).

giampaolo/pyftpdlib