TypeError in MerkleTree Properties in Python 3.8 Environment

[olivmath]

Environment

• Python Version: 3.8
• Library Version: [Versão da biblioteca, se aplicável]

Description of the Issue

When running tests using Python 3.8, a TypeError is encountered in the MerkleTree class, specifically in the human_leaves and human_short_leaves properties. This issue does not occur in Python 3.9 or 3.10, indicating it's likely related to type hinting compatibility with Python 3.8.

Error Message

TypeError: 'type' object is not subscriptable

This error occurs when collecting tests that import and use the MerkleTree class.

Steps to Reproduce

1. Set up a Python 3.8 environment.
2. Run pytest on the codebase.
3. Observe the TypeError in the collection phase of the pytest.

Expected Behavior

The MerkleTree class should function correctly without type errors across different Python versions, especially in supported versions like Python 3.8.

Actual Behavior

A TypeError is raised due to the use of Python 3.9+ style list type hints (e.g., list[str]) which are not compatible with Python 3.8.

Possible Solution

Replace the Python 3.9+ list type hints with the Python 3.8 compatible format using the typing module. For instance, change:

@property
def human_leaves(self) -> list[str]:
    ...

to

from typing import List

@property
def human_leaves(self) -> List[str]:
    ...

and similarly for human_short_leaves.