Simple libnotify implementation using only plain dbus-send. Can close created notification.

simple_notify.py

import sys
from subprocess import Popen, PIPE

def notify(title, body=None, timeout=-1, appname='simple-notify'):
    cmd = [
        'dbus-send',
        '--type=method_call',
        '--print-reply=literal',
        '--dest=org.freedesktop.Notifications',
        '/org/freedesktop/Notifications',
        'org.freedesktop.Notifications.Notify',
        'string:{}'.format(appname),
        'uint32:0',
        'string:""',
        'string:{}'.format(title),
        'string:{}'.format(body),
        'array:string:""',
        'dict:string:string:"",""',
        'int32:{}'.format(timeout),
    ]

    out, err = Popen(cmd, stdout=PIPE, stderr=PIPE).communicate()
    if err:
        raise Exception(err)

    return int(out.strip().split()[1])

def close(nid):
    cmd = [
        'dbus-send',
        '--type=method_call',
        '--dest=org.freedesktop.Notifications',
        '/org/freedesktop/Notifications',
        'org.freedesktop.Notifications.CloseNotification',
        'int32:{}'.format(nid),
    ]

    out, err = Popen(cmd, stdout=PIPE, stderr=PIPE).communicate()
    if err:
        raise Exception(err)

if __name__ == '__main__':
    if sys.argv[1] == 'close':
        close(sys.argv[2])
    else:
        print notify(*sys.argv[1:4])

You can use gdbus call, though