diff --git a/leetcode/api_client.py b/leetcode/api_client.py

index 8b27247..8092ae5 100644

--- a/leetcode/api_client.py

+++ b/leetcode/api_client.py

@@ -10,6 +10,7 @@

"""

from __future__ import absolute_import

+import atexit

import datetime

import json

import mimetypes

@@ -66,6 +67,7 @@ class ApiClient(object):

self.configuration = configuration

self.pool = ThreadPool()

+ atexit.register(self._close_pool)

self.rest_client = rest.RESTClientObject(configuration)

self.default_headers = {}

if header_name is not None:

@@ -74,7 +76,7 @@ class ApiClient(object):

# Set default User-Agent.

self.user_agent = 'Swagger-Codegen/1.0.0/python'

- def __del__(self):

+ def _close_pool(self):

self.pool.close()

self.pool.join()