@property<EOL><INDENT>def is_root(self):<DEDENT>
return self.parent is None<EOL>
`Node` is tree root.

>>> from anytree import Node
>>> udo = Node("Udo")
>>> marc = Node("Marc", parent=udo)
>>> lian = Node("Lian", parent=marc)
>>> udo.is_root
True
>>> marc.is_root
False
>>> lian.is_root
False