code: def rightsibling(node):
      
      if node.parent:
          pchildren = node.parent.children
          idx = pchildren.index(node)
          try:
              return pchildren[idx + 1]
          except IndexError:
              return None
      else:
          return None
docs: Return Right Sibling of `node`.
  
      >>> from anytree import Node
      >>> dan = Node("Dan")
      >>> jet = Node("Jet", parent=dan)
      >>> jan = Node("Jan", parent=dan)
      >>> joe = Node("Joe", parent=dan)
      >>> rightsibling(dan)
      >>> rightsibling(jet)
      Node('/Dan/Jan')
      >>> rightsibling(jan)
      Node('/Dan/Joe')
      >>> rightsibling(joe)