import subprocess, json

class MountException(Exception):

    pass

def mount(source, target, fs, options=''):

    NotImplementedError('Not yet')

def is_mounted(device):

    proc = subprocess.Popen(['findmnt', '-J', device], stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    result = proc.wait()

    if result == 1:

        return False

    output = proc.stdout.read().decode('utf')

    if output:

        output = json.loads(output)

        return len(output['filesystems']) > 0

    else:

        return False

def unmount(device):

    proc = subprocess.Popen(['umount', device], stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    if proc.wait() != 0:

        raise MountException(proc.stderr.read().decode('utf8'))