socket.error: [Errno 48] Address already in use

socket.error: [Errno 48] Address already in use

I'm trying to set up a server with python from mac command line.
I navigate to folder location an use:
python -m SimpleHTTPServer
But this gives me error:
socket.error: [Errno 48] Address already in use
I had previously open a connection using the same command for a different
website in a different location in my machine.