# Buggy code
def load_keystore(db, name) -> KeyStore:
    d = db.get(name, {})
    t = d.get("type")
    if not t:
        raise WalletFileException(
            "Wallet format requires update.\nCannot find keystore for name {}".format(
                name
            )
        )
    keystore_constructors = {
        ks.type: ks for ks in [Old_KeyStore, Imported_KeyStore, BIP32_KeyStore]
    }
    keystore_constructors["hardware"] = hardware_keystore
    try:
        ks_constructor = keystore_constructors[t]
    except KeyError:
        raise WalletFileException(f"Unknown type {t} for keystore named {name}")
    k = ks_constructor(d)
    return k


# Traceback (TypeError)
E | gui.qt.exception_window.Exception_Hook | exception caught by crash reporter
Traceback (most recent call last):
File "...\electrum\electrum\gui\qt\main_window.py", line 2838, in closeEvent
self.clean_up()
File "...\electrum\electrum\gui\qt\main_window.py", line 2856, in clean_up
self.gui_object.close_window(self)
File "...\electrum\electrum\gui\qt\__init__.py", line 339, in close_window
self.daemon.stop_wallet(window.wallet.storage.path)
File "...\electrum\electrum\daemon.py", line 453, in stop_wallet
wallet.stop_threads()
File "...\electrum\electrum\wallet.py", line 314, in stop_threads
self.save_keystore()
File "...\electrum\electrum\wallet.py", line 1908, in save_keystore
self.db.put('keystore', self.keystore.dump())
File "...\electrum\electrum\json_db.py", line 38, in wrapper
return func(self, *args, **kwargs)
File "...\electrum\electrum\json_db.py", line 184, in put
self.data[key] = copy.deepcopy(value)
File "...\Python38\lib\copy.py", line 146, in deepcopy
y = copier(x, memo)
File "...\Python38\lib\copy.py", line 230, in _deepcopy_dict
y[deepcopy(key, memo)] = deepcopy(value, memo)
File "...\Python38\lib\copy.py", line 172, in deepcopy
y = _reconstruct(x, memo, *rv)
File "...\Python38\lib\copy.py", line 270, in _reconstruct
state = deepcopy(state, memo)
File "...\Python38\lib\copy.py", line 146, in deepcopy
y = copier(x, memo)
File "...\Python38\lib\copy.py", line 230, in _deepcopy_dict
y[deepcopy(key, memo)] = deepcopy(value, memo)
File "...\Python38\lib\copy.py", line 172, in deepcopy
y = _reconstruct(x, memo, *rv)
File "...\Python38\lib\copy.py", line 270, in _reconstruct
state = deepcopy(state, memo)
File "...\Python38\lib\copy.py", line 146, in deepcopy
y = copier(x, memo)
File "...\Python38\lib\copy.py", line 230, in _deepcopy_dict
y[deepcopy(key, memo)] = deepcopy(value, memo)
File "...\Python38\lib\copy.py", line 161, in deepcopy
rv = reductor(4)
TypeError: cannot pickle '_thread.RLock' object

# Fixed code
def load_keystore(db: "WalletDB", name: str) -> KeyStore:
    d = db.get(name, {})
    d = dict(d)  # convert to dict from StoredDict (see #6066)
    t = d.get("type")
    if not t:
        raise WalletFileException(
            "Wallet format requires update.\nCannot find keystore for name {}".format(
                name
            )
        )
    keystore_constructors = {
        ks.type: ks for ks in [Old_KeyStore, Imported_KeyStore, BIP32_KeyStore]
    }
    keystore_constructors["hardware"] = hardware_keystore
    try:
        ks_constructor = keystore_constructors[t]
    except KeyError:
        raise WalletFileException(f"Unknown type {t} for keystore named {name}")
    k = ks_constructor(d)
    return k