# Path: anytree/iterators/abstractiter.py
# class AbstractIter(six.Iterator):
# 
#     def __init__(self, node, filter_=None, stop=None, maxlevel=None):
#         """
#         Iterate over tree starting at `node`.
# 
#         Base class for all iterators.
# 
#         Keyword Args:
#             filter_: function called with every `node` as argument, `node` is returned if `True`.
#             stop: stop iteration at `node` if `stop` function returns `True` for `node`.
#             maxlevel (int): maximum descending in the node hierarchy.
#         """
#         self.node = node
#         self.filter_ = filter_
#         self.stop = stop
#         self.maxlevel = maxlevel
#         self.__iter = None
# 
#     def __init(self):
#         node = self.node
#         maxlevel = self.maxlevel
#         filter_ = self.filter_ or AbstractIter.__default_filter
#         stop = self.stop or AbstractIter.__default_stop
#         children = [] if AbstractIter._abort_at_level(1, maxlevel) else AbstractIter._get_children([node], stop)
#         return self._iter(children, filter_, stop, maxlevel)
# 
#     @staticmethod
#     def __default_filter(node):
#         return True
# 
#     @staticmethod
#     def __default_stop(node):
#         return False
# 
#     def __iter__(self):
#         return self
# 
#     def __next__(self):
#         if self.__iter is None:
#             self.__iter = self.__init()
#         return next(self.__iter)
# 
#     @staticmethod
#     def _iter(children, filter_, stop, maxlevel):
#         raise NotImplementedError()  # pragma: no cover
# 
#     @staticmethod
#     def _abort_at_level(level, maxlevel):
#         return maxlevel is not None and level > maxlevel
# 
#     @staticmethod
#     def _get_children(children, stop):
#         return [child for child in children if not stop(child)]


from .abstractiter import AbstractIter
    |       +-- e
    +-- g
        +-- i
            +-- h
    >>> [[node.name for node in children] for children in LevelOrderGroupIter(f)]
    [['f'], ['b', 'g'], ['a', 'd', 'i'], ['c', 'e', 'h']]
    >>> [[node.name for node in children] for children in LevelOrderGroupIter(f, maxlevel=3)]
    [['f'], ['b', 'g'], ['a', 'd', 'i']]
    >>> [[node.name for node in children]
    ...  for children in LevelOrderGroupIter(f, filter_=lambda n: n.name not in ('e', 'g'))]
    [['f'], ['b'], ['a', 'd', 'i'], ['c', 'h']]
    >>> [[node.name for node in children]
    ...  for children in LevelOrderGroupIter(f, stop=lambda n: n.name == 'd')]
    [['f'], ['b', 'g'], ['a', 'i'], ['h']]
    """

    @staticmethod
    def _iter(children, filter_, stop, maxlevel):
        level = 1
        while children:
            yield tuple([child for child in children if filter_(child)])
            level += 1
            if AbstractIter._abort_at_level(level, maxlevel):
                break
            children = LevelOrderGroupIter._get_grandchildren(children, stop)

    @staticmethod
    def _get_grandchildren(children, stop):
        next_children = []
        for child in children:

# Path: anytree/iterators/abstractiter.py
# class AbstractIter(six.Iterator):
# 
#     def __init__(self, node, filter_=None, stop=None, maxlevel=None):
#         """
#         Iterate over tree starting at `node`.
# 
#         Base class for all iterators.
# 
#         Keyword Args:
#             filter_: function called with every `node` as argument, `node` is returned if `True`.
#             stop: stop iteration at `node` if `stop` function returns `True` for `node`.
#             maxlevel (int): maximum descending in the node hierarchy.
#         """
#         self.node = node
#         self.filter_ = filter_
#         self.stop = stop
#         self.maxlevel = maxlevel
#         self.__iter = None
# 
#     def __init(self):
#         node = self.node
#         maxlevel = self.maxlevel
#         filter_ = self.filter_ or AbstractIter.__default_filter
#         stop = self.stop or AbstractIter.__default_stop
#         children = [] if AbstractIter._abort_at_level(1, maxlevel) else AbstractIter._get_children([node], stop)
#         return self._iter(children, filter_, stop, maxlevel)
# 
#     @staticmethod
#     def __default_filter(node):
#         return True
# 
#     @staticmethod
#     def __default_stop(node):
#         return False
# 
#     def __iter__(self):
#         return self
# 
#     def __next__(self):
#         if self.__iter is None:
#             self.__iter = self.__init()
#         return next(self.__iter)
# 
#     @staticmethod
#     def _iter(children, filter_, stop, maxlevel):
#         raise NotImplementedError()  # pragma: no cover
# 
#     @staticmethod
#     def _abort_at_level(level, maxlevel):
#         return maxlevel is not None and level > maxlevel
# 
#     @staticmethod
#     def _get_children(children, stop):
#         return [child for child in children if not stop(child)]


# Path: anytree/iterators/levelordergroupiter.py
from .abstractiter import AbstractIter

    |       +-- e
    +-- g
        +-- i
            +-- h
    >>> [[node.name for node in children] for children in LevelOrderGroupIter(f)]
    [['f'], ['b', 'g'], ['a', 'd', 'i'], ['c', 'e', 'h']]
    >>> [[node.name for node in children] for children in LevelOrderGroupIter(f, maxlevel=3)]
    [['f'], ['b', 'g'], ['a', 'd', 'i']]
    >>> [[node.name for node in children]
    ...  for children in LevelOrderGroupIter(f, filter_=lambda n: n.name not in ('e', 'g'))]
    [['f'], ['b'], ['a', 'd', 'i'], ['c', 'h']]
    >>> [[node.name for node in children]
    ...  for children in LevelOrderGroupIter(f, stop=lambda n: n.name == 'd')]
    [['f'], ['b', 'g'], ['a', 'i'], ['h']]
    """

    @staticmethod
    def _iter(children, filter_, stop, maxlevel):
        level = 1
        while children:
            yield tuple([child for child in children if filter_(child)])
            level += 1
            if AbstractIter._abort_at_level(level, maxlevel):
                break
            children = LevelOrderGroupIter._get_grandchildren(children, stop)

    @staticmethod
    def _get_grandchildren(children, stop):
        next_children = []
        for child in children:

            next_children = next_children + AbstractIter._get_children(child.children, stop)