cursor closes without explicit close

[Coyot Linden (Glenn Glazer)]

For various reasons, including secrets handling, singleton connections
and so forth, I have a DBManager class that provides a DictCursor to
clients.

During instance initialization, the following are called in sequence:

    def get_handle(self, name: str = None, logger: LoginLogger = None):
        try:
            self.conn = pymysql.connect(host=self.dsn,
                                        user=self.db_user,
                                        password=self.db_pass,
database=name.split('.')[1],
cursorclass=pymysql.cursors.DictCursor,
                                        charset='utf8',
                                        autocommit=True)
        except Exception as e:
            logger.log_msg('error', "exception trying to connect to %s
db: %r" % (name, e))
            return False
        return True

    def _get_cursor(self):
        # https://pymysql.readthedocs.io/en/latest/user/examples.html
        with self.conn:
            with self.conn.cursor() as cursor:
                self.cursor = cursor

and then clients can call:

    def get_cursor(self):
        return self.cursor

When I create a conn and get a cursor outside of a class in a python
shell using the same code and credentials, all is well. But when I do this:

dbc = dbm.get_cursor()
assert isinstance(dbc, DictCursor), "got back something that isn't a
DictCursor: %s" % type(dbc)
print("%r" % dbc)
rows = dbc.execute("SELECT 123")

I get (and note that the assert did not fail):

<pymysql.cursors.DictCursor object at 0x7f29d422d2e8>
Traceback (most recent call last):
  File "./DBManagerTest.py", line 54, in <module>
    rows = dbc.execute("SELECT 123")
  File "/usr/lib/python3/dist-packages/pymysql/cursors.py", line 165,
in execute
    while self.nextset():
  File "/usr/lib/python3/dist-packages/pymysql/cursors.py", line 107,
in nextset
    return self._nextset(False)
  File "/usr/lib/python3/dist-packages/pymysql/cursors.py", line 91, in
_nextset
    conn = self._get_db()
  File "/usr/lib/python3/dist-packages/pymysql/cursors.py", line 73, in
_get_db
    raise err.ProgrammingError("Cursor closed")
pymysql.err.ProgrammingError: Cursor closed

So I would appreciate suggestions on how to fix this so that cursor
stays open for even one query.

Best,

coyot