chore: add return type hint to ContractId.__str__ (hiero-ledger#1655)

Signed-off-by: Luis Fuentes <luisayan100@gmail.com>
Signed-off-by: Flames4fun <125478683+Flames4fun@users.noreply.github.com>

Author: Flames4fun

CHANGELOG.md

@@ -228,6 +228,8 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Enhance TopicInfo `__str__` method and tests with additional coverage, and update the format_key function in `key_format.py` to handle objects with a \_to_proto method.
 - Update changelog workflow to trigger automatically on pull requests instead of manual dispatch (#1567)
 - Formatted key-related unit test files (`key_utils_test.py`, `test_key_format.py`, `test_key_list.py`) using the black formatter
+- Add return type hint to `ContractId.__str__`. (#1654)
+
 - chore: update maintainer guidelines link in MAINTAINERS.md (#1605)
 - chore: update merge conflict bot message with web editor tips (#1592)
 
@@ -837,3 +839,6 @@ contract_call_local_pb2.ContractLoginfo -> contract_types_pb2.ContractLoginfo
 ### Removed
 
 - N/A
+
+
+# [0.1.0] - 2025-02-19

src/hiero_sdk_python/contract/contract_id.py

@@ -134,7 +134,7 @@ def from_string(cls, contract_id_str: str) -> "ContractId":
                     f"Expected format 'shard.realm.contract'."
                 ) from e
 
-    def __str__(self):
+    def __str__(self) -> str:
         """
         Returns the string representation of the ContractId.