old_contents: from abc import abstractmethod, abstractproperty
  from typing import List, Tuple
  
  
  class MerkleTree:
      """
      Interface to be implemented by all Merkle Trees.
      """
  
      @abstractmethod
      def append(self, new_leaf):
          """
          """
  
      @abstractmethod
      def merkle_tree_hash(self, start, end):
          """
          """
  
      @abstractmethod
      def consistency_proof(self, first, second):
          """
          """
  
      @abstractmethod
      def inclusion_proof(self, start, end):
          """
          """
  
      @abstractmethod
      def get_tree_head(self, seq=None):
          """
          """
  
      @abstractproperty
      def hashes(self) -> Tuple[bytes]:
          """
          """
  
      @abstractproperty
      def root_hash(self) -> bytes:
          """
          """
  
      @abstractproperty
      def root_hash_hex(self) -> bytes:
          """
          """
  
      @abstractproperty
      def tree_size(self) -> int:
          """
          """
  
      @abstractproperty
      def leafCount(self) -> int:
          """
          """
  
      @abstractproperty
      def nodeCount(self) -> int:
          """
          """
new_contents: from abc import abstractmethod, abstractproperty
  from typing import List, Tuple
  
  
  class MerkleTree:
      """
      Interface to be implemented by all Merkle Trees.
      """
  
      @abstractmethod
      def append(self, new_leaf):
          """
          """
  
      @abstractmethod
      def merkle_tree_hash(self, start, end):
          """
          """
  
      @abstractmethod
      def consistency_proof(self, first, second):
          """
          """
  
      @abstractmethod
      def inclusion_proof(self, start, end):
          """
          """
  
      @abstractmethod
      def get_tree_head(self, seq=None):
          """
          """
  
      @abstractproperty
      def hashes(self) -> Tuple[bytes]:
          """
          """
  
      @abstractproperty
      def root_hash(self) -> bytes:
          """
          """
  
      @abstractproperty
      def root_hash_hex(self) -> bytes:
          """
          """
  
      @abstractproperty
      def tree_size(self) -> int:
          """
          """
  
      @abstractproperty
      def leafCount(self) -> int:
          """
          """
  
      @abstractproperty
      def nodeCount(self) -> int:
          """
          """
  
      @abstractmethod
      def verifyConsistency(self) -> bool:
          """
          """
subject: add verifyConsistency method to MerkleTree