Add cluster_tree attribute and predict function to BAHC

Author: Krsto Proroković

unsupervised_bias_detection/cluster/_cluster_node.py

@@ -0,0 +1,54 @@
+from sklearn.base import ClusterMixin
+from typing import Self
+
+class ClusterNode:
+    def __init__(self, label: int):
+        """
+        Initialize a node in the cluster tree
+        
+        Parameters:
+        -----------
+        label : int
+            The cluster label for this node (required as all nodes start as leaves)
+        """
+        self.label = label
+        self.clustering_model = None
+        self.children = []
+    
+    @property
+    def is_leaf(self):
+        return len(self.children) == 0
+    
+    def split(self, clustering_model: ClusterMixin, children: list[Self]):
+        """
+        Split this node by setting its clustering model and adding children
+        
+        This converts the node to an internal node and removes its label
+        
+        Parameters:
+        -----------
+        clustering_model : ClusterMixin
+            The clustering model used to split this node
+        children : list of ClusterNode
+            The child nodes resulting from the split
+        """   
+        self.label = None
+        self.clustering_model = clustering_model
+        self.children = children
+    
+    def get_leaves(self) -> list[Self]:
+        """
+        Get all leaf nodes in the subtree rooted at this node
+        
+        Returns:
+        --------
+        list of ClusterNode
+            All leaf nodes in the subtree
+        """
+        if not self.children:
+            return [self]
+        
+        leaves = []
+        for child in self.children:
+            leaves.extend(child.get_leaves())
+        return leaves