38     previousSibling = None  variable in Node
102             refChild.previousSibling = newChild
106                 newChild.previousSibling = node
108                 newChild.previousSibling = None
152         newChild.previousSibling = oldChild.previousSibling
154         oldChild.previousSibling = None
155         if newChild.previousSibling:
156             newChild.previousSibling.nextSibling = newChild
158             newChild.nextSibling.previousSibling = newChild
167             oldChild.nextSibling.previousSibling = oldChild.previousSibling
168         if oldChild.previousSibling is not None:
169             oldChild.previousSibling.nextSibling = oldChild.nextSibling
170         oldChild.nextSibling = oldChild.previousSibling = None
186                         child.nextSibling.previousSibling = child.previousSibling
194                         child.nextSibling.previousSibling = node
267         self.previousSibling = None
1044         n = self.previousSibling
1048                 n = n.previousSibling
1064         n = self.previousSibling
1067                 next = n.previousSibling
1484     previousSibling = nextSibling = None  variable in Document
1560         oldChild.nextSibling = oldChild.previousSibling = None