code: def balanced_binary_tree(n_leaves):
      
      def _balanced_subtree(leaves):
          if len(leaves) == 1:
              return leaves[0]
          elif len(leaves) == 2:
              return (leaves[0], leaves[1])
          else:
              split = len(leaves) // 2
              return (_balanced_subtree(leaves[:split]),
                      _balanced_subtree(leaves[split:]))
  
      return _balanced_subtree(np.arange(n_leaves))
docs: Create a balanced binary tree