'Get snapshot by name from the snapshot tree root.
:param name: Snapshot name
:param root: Current root node in the snapshot tree
:return: None in the snapshot tree with given snapshot name'

@staticmethod
def _get_snapshot_from_tree(name, root):

    if (not root):
        return None
    if (root.name == name):
        return root.snapshot
    if ((not hasattr(root, 'childSnapshotList')) or (not root.childSnapshotList)):
        return None
    for node in root.childSnapshotList:
        snapshot = VMwareVolumeOps._get_snapshot_from_tree(name, node)
        if snapshot:
            return snapshot
