Get the tree branches as list.

        Returns:
            list: A 2d-list holding the grown branches coordinates as tupel for every age.
                Example:
                [
                [(10, 40, 90, 30)],
                [(90, 30, 100, 40), (90, 30, 300, 60)],
                [(100, 40, 120, 70), (100, 40, 150, 90), ...],
                ...
                ]

def get_branches(self):
        """Get the tree branches as list.

        Returns:
            list: A 2d-list holding the grown branches coordinates as tupel for every age.
                Example:
                [
                [(10, 40, 90, 30)],
                [(90, 30, 100, 40), (90, 30, 300, 60)],
                [(100, 40, 120, 70), (100, 40, 150, 90), ...],
                ...
                ]
        """
        branches = []
        for age, level in enumerate(self.nodes):
            branches.append([])
            for n, node in enumerate(level):
                if age == 0:
                    p_node = Node(self.pos[:2])
                else:
                    p_node = self._get_node_parent(age-1, n)
                branches[age].append(p_node.get_tuple() + node.get_tuple())

        return branches