39     previousSibling = None  variable in Node
103             refChild.previousSibling = newChild
107                 newChild.previousSibling = node
109                 newChild.previousSibling = None
153         newChild.previousSibling = oldChild.previousSibling
155         oldChild.previousSibling = None
156         if newChild.previousSibling:
157             newChild.previousSibling.nextSibling = newChild
159             newChild.nextSibling.previousSibling = newChild
168             oldChild.nextSibling.previousSibling = oldChild.previousSibling
169         if oldChild.previousSibling is not None:
170             oldChild.previousSibling.nextSibling = oldChild.nextSibling
171         oldChild.nextSibling = oldChild.previousSibling = None
187                         child.nextSibling.previousSibling = child.previousSibling
195                         child.nextSibling.previousSibling = node
268         self.previousSibling = None
289         node.previousSibling = last
685         self.nextSibling = self.previousSibling = None
996         self.previousSibling = self.nextSibling = None
1094         n = self.previousSibling
1098                 n = n.previousSibling
1114         n = self.previousSibling
1117                 next = n.previousSibling
1531     previousSibling = nextSibling = None  variable in Document
1607         oldChild.nextSibling = oldChild.previousSibling = None