feat: implement inorder traversal of ranked tree

Fixes #4

Signed-off-by: Matej Focko <mfocko@redhat.com>

node.py

@@ -1,6 +1,14 @@
 from abc import abstractmethod
 import enum
-from typing import Callable, Optional, Generic, Tuple, TypeVar, Protocol
+from typing import (
+    Callable,
+    Iterable,
+    Optional,
+    Generic,
+    Tuple,
+    TypeVar,
+    Protocol,
+)
 
 
 class Comparable(Protocol):
@@ -54,6 +62,17 @@ class Node(Generic[T]):
     def __str__(self) -> str:
         return f"Node(value={self.value}, rank={self.rank})"
 
+    def __iter__(self) -> Iterable[T]:
+        """
+        Yields:
+            Keys from the subtree rooted at the node in an inorder fashion.
+        """
+        if self.left:
+            yield from self.left
+        yield self.value
+        if self.right:
+            yield from self.right
+
     @staticmethod
     def height(node: "Optional[Node[T]]") -> int:
         return (

ranked_tree.py

@@ -3,7 +3,7 @@ from node import Node, Comparable
 from abc import abstractmethod
 from collections import deque
 import logging
-from typing import Deque, Optional, Tuple, TypeVar, Generic
+from typing import Deque, Iterable, Optional, Tuple, TypeVar, Generic
 
 logger = logging.getLogger(__name__)
 T = TypeVar("T", bound=Comparable)
@@ -140,3 +140,11 @@ class RankedTree(Generic[T]):
         if to_be_rebalanced := self._delete(value):
             y, parent = to_be_rebalanced
             self._delete_rebalance(y, parent)
+
+    def __iter__(self) -> Iterable[T]:
+        """
+        Yields:
+            Keys from the tree in an inorder fashion.
+        """
+        if self.root:
+            yield from self.root