code: def sibling(self, offs=1):
          '''
          Return sibling node by relative offset from self.
          '''
          indx = self.pindex + offs
  
          if indx < 0:
              return None
  
          if indx >= len(self.parent.kids):
              return None
  
          return self.parent.kids[indxf sibling(self, offs=1):
          '''
          Return sibling node by relative offset from self.
          '''
          indx = self.pindex + offs
  
          if indx < 0:
              return None
  
          if indx >= len(self.parent.kids):
              return None
  
          return self.parent.kids[indx]
docs: Return sibling node by relative offset from self.