Not running after not closing properly

[Даниил Николаев (NeverMine)]

Python says:

# python ./dsvw.py
Damn Small Vulnerable Web (DSVW) < 100 LoC (Lines of Code) #v0.1m
 by: Miroslav Stampar (@stamparm)

[i] running HTTP server at '127.0.0.1:65412'...
Traceback (most recent call last):
  File "./dsvw.py", line 90, in <module>
    ThreadingServer((LISTEN_ADDRESS, LISTEN_PORT), ReqHandler).serve_forever()
  File "/usr/lib/python2.7/SocketServer.py", line 417, in __init__
    self.server_bind()
  File "/usr/lib/python2.7/BaseHTTPServer.py", line 108, in server_bind
    SocketServer.TCPServer.server_bind(self)
  File "/usr/lib/python2.7/SocketServer.py", line 431, in server_bind
    self.socket.bind(self.server_address)
  File "/usr/lib/python2.7/socket.py", line 228, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 98] Address already in use

lsb_release -a says:

# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.1 LTS
Release:	16.04
Codename:	xenial