import sys
class ListPrinter:
    """Print a fennec::list"""

    class Iterator:
        def __init__(self, head):
            self.node = head

        def __iter__(self):
            return self

        def __next__(self):
            if self.node == sys.maxsize:
                raise StopIteration
            value = self.node['*data']
            self.node = self.node['_data[next]']
            return value

    def __init__(self, val):
        self.val = val

    def to_string(self):
        return "fennec::list"

    def children(self):
        return enumerate(self.Iterator(self.val['_data[_root]']))