'Return vdisk_UID for given vdisk.
Given a vdisk by name, performs an lvdisk command that extracts
the vdisk_UID parameter and returns it.
Returns None if the specified vdisk does not exist.'

def _get_vdisk_uid(self, vdisk_name):

    (vdisk_properties, _err) = self.sim._cmd_lsvdisk(obj=vdisk_name, delim='!')
    for row in vdisk_properties.split('\n'):
        words = row.split('!')
        if (words[0] == 'vdisk_UID'):
            return words[1]
    return None
