I use it to check whether NFS is writable, I do not see NFS close the connection
nfs = libnfs.NFS("nfs://{server}{path}".format(server=nfs_server, path=nfs_path))
f = nfs.open("/test_nfs_rw.file", "w")
f.write(str(time.time()))
f.close()
Have you closed the connection?