'Given a volume snap info, retrieve the snapVx object.
:param array: the array serial number
:param device_id: the source volume device id
:param snap_name: the name of the snapshot
:returns: snapshot dict, or None'

def get_volume_snap(self, array, device_id, snap_name):

    snapshot = None
    snap_info = self.get_volume_snap_info(array, device_id)
    if snap_info:
        if (snap_info.get('snapshotSrcs') and bool(snap_info['snapshotSrcs'])):
            for snap in snap_info['snapshotSrcs']:
                if (snap['snapshotName'] == snap_name):
                    snapshot = snap
    return snapshot
