## ThreadPoolExecutor
```py
__import__('concurrent').futures.ThreadPoolExecutor().submit(
   lambda x: (print(x * 2) or x ** 2 / 0), 3).result()
```

## zmq.REQ
```py
def File(blob):
   try: import zmq; File.sock.send_pyobj(blob); return File.sock.recv_pyobj()
   except (AttributeError, zmq.Again):
      (sock := zmq.Context().socket(zmq.REQ)).connect('tcp://localhost:6106')
      sock.RCVTIMEO = 1000; File.sock = sock; return File(blob)
```

## sqlite3
```py
def SQL():
   def File(blob):
      try: import zmq; File.sock.send_pyobj(blob); return File.sock.recv_pyobj()
      except (AttributeError, zmq.Again):
         (sock := zmq.Context().socket(zmq.REQ)).connect('tcp://localhost:6106')
         sock.RCVTIMEO = 1000; File.sock = sock; return File(blob)

    import sqlite3
    (con := sqlite3.connect('.db', isolation_level=None)).row_factory = sqlite3.Row
    con.executescript("""
        PRAGMA journal_mode=WAL;
        CREATE TABLE IF NOT EXISTS kv(k, v, t DEFAULT CURRENT_TIMESTAMP);
        CREATE INDEX IF NOT EXISTS index_kv_v ON kv(v);
        CREATE INDEX IF NOT EXISTS index_kv_k_t ON kv(k, t DESC);
    """)
    def setitem(sql, filename, blob):
        assert isinstance(blob, bytes)
        sql('INSERT INTO kv(k, v) VALUES(?,?)', filename, File(blob))
    def getitem(sql, filename):
        if sha1 := sql('SELECT v FROM kv WHERE k=? ORDER BY t DESC', filename):
            return File(sha1[0]['v'])
    def contains(sql, filename):
        return bool(sql('SELECT 1 FROM kv WHERE k=?', filename))
    def df(sql):
        import pandas as pd
        return pd.DataFrame(sql('SELECT * FROM kv'))
    return type('', (), dict(__call__=lambda _, q, *p: list(map(dict, con.execute(q, p))),
        __setitem__=setitem, __getitem__=getitem, __contains__=contains, df=df))()
sql = SQL()
```