ClearDBのデフォルトの接続文字列でキーワード引数を再接続すると、MySQLdbでエラーが発生します

DjangoアプリをHerokuにアップロードし、Herokuドキュメントの次の3つのコマンドを使用してcleardbアドオンをプロビジョニングしました。

heroku addons:create cleardb:ignite
heroku config | grep CLEARDB_DATABASE_URL
heroku config:set DATABASE_URL='mysql://adffdadf2341:[email protected]/heroku_db?reconnect=true'

それは問題ないようで、アプリは実行されています（ただしデータベースはありません）。今私は実行しようとします：

$ heroku run python manage.py migrate

そしてこれは私が得るエラーです：

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 327, in execute
    self.check()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 359, in check
    include_deployment_checks=include_deployment_checks,
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 61, in _run_checks
    issues = run_checks(tags=[Tags.database])
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/checks/registry.py", line 81, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/checks/database.py", line 10, in check_database_backends
    issues.extend(conn.validation.check(**kwargs))
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/mysql/validation.py", line 9, in check
    issues.extend(self._check_sql_mode(**kwargs))
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/mysql/validation.py", line 13, in _check_sql_mode
    with self.connection.cursor() as cursor:
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/base/base.py", line 254, in cursor
    return self._cursor()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/base/base.py", line 229, in _cursor
    self.ensure_connection()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/base/base.py", line 213, in ensure_connection
    self.connect()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/base/base.py", line 189, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/db/backends/mysql/base.py", line 274, in get_new_connection
    conn = Database.connect(**conn_params)
  File "/app/.heroku/python/lib/python3.5/site-packages/MySQLdb/__init__.py", line 86, in Connect
    return Connection(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.5/site-packages/MySQLdb/connections.py", line 204, in __init__
    super(Connection, self).__init__(*args, **kwargs2)
TypeError: 'reconnect' is an invalid keyword argument for this function

問題はどこから発生し、どうすれば修正できますか？