If I had to do this in production code I wouldn't do it that way (for a start I prefer static data structures where possible). I'd have 2 classes: BinaryTree and DoubleLinkedList, each of which would have a constructor that takes a list as input, and a function that returns the data as a list:

    class BinaryTree:
        def __init__(self, data: List):
            """ create from a list """
        def asList(self)->List:
            """ return my data as a list """

    class DoubleLinkedList:
        def __init__(self, data: List):
            """ create from a list """
        def asList(self)->List:
            """ return my data as a list """

Then making a binary tree from a double-linked list is simply:

    BinaryTree(dll.asList())