# Buggy code
def remember_node(self, node, force_verification_check=False, record_fleet_state=True):
    if node == self:  # No need to remember self.
        return False

    # First, determine if this is an outdated representation of an already known node.
    # TODO: #1032
    with suppress(KeyError):
        already_known_node = self.known_nodes[node.checksum_address]
        if not node.timestamp > already_known_node.timestamp:
            self.log.debug("Skipping already known node {}".format(already_known_node))
            # This node is already known.  We can safely return.
            return False

    try:
        stranger_certificate = node.certificate
    except AttributeError:
        # Whoops, we got an Alice, Bob, or someone...
        raise self.NotATeacher(
            f"{node.__class__.__name__} does not have a certificate and cannot be remembered."
        )

    # Store node's certificate - It has been seen.
    certificate_filepath = self.node_storage.store_node_certificate(
        certificate=stranger_certificate
    )

    # In some cases (seed nodes or other temp stored certs),
    # this will update the filepath from the temp location to this one.
    node.certificate_filepath = certificate_filepath
    self.log.info(f"Saved TLS certificate for {node.nickname}: {certificate_filepath}")

    try:
        node.verify_node(
            force=force_verification_check,
            network_middleware=self.network_middleware,
            accept_federated_only=self.federated_only,  # TODO: 466 - move federated-only up to Learner?
        )
    except SSLError:
        return False  # TODO: Bucket this node as having bad TLS info - maybe it's an update that hasn't fully propagated?

    except NodeSeemsToBeDown:
        self.log.info(
            "No Response while trying to verify node {}|{}".format(
                node.rest_interface, node
            )
        )
        return False  # TODO: Bucket this node as "ghost" or something: somebody else knows about it, but we can't get to it.

    listeners = self._learning_listeners.pop(node.checksum_address, tuple())
    address = node.checksum_address

    self.known_nodes[address] = node

    if self.save_metadata:
        self.node_storage.store_node_metadata(node=node)

    self.log.info(
        "Remembering {} ({}), popping {} listeners.".format(
            node.nickname, node.checksum_address, len(listeners)
        )
    )
    for listener in listeners:
        listener.add(address)
    self._node_ids_to_learn_about_immediately.discard(address)

    if record_fleet_state:
        self.known_nodes.record_fleet_state()

    return node


# Traceback (ValueError)
$ nucypher ursula confirm-activity



,ggg,         gg
dP""Y8a        88                                   ,dPYb,
Yb, `88        88                                   IP'`Yb
`"  88        88                                   I8  8I
88        88                                   I8  8'
88        88   ,gggggg,    ,g,     gg      gg  I8 dP    ,gggg,gg
88        88   dP""""8I   ,8'8,    I8      8I  I8dP    dP"  "Y8I
88        88  ,8'    8I  ,8'  Yb   I8,    ,8I  I8P    i8'    ,8I
Y8b,____,d88,,dP     Y8,,8'_   8) ,d8b,  ,d8b,,d8b,_ ,d8,   ,d8b,
"Y888888P"Y88P      `Y8P' "YY8P8P8P'"Y88P"`Y88P'"Y88P"Y8888P"`Y8


the Untrusted Re-Encryption Proxy.


Decrypting NuCypher keyring...
WARNING - No Bootnodes Available
Traceback (most recent call last):
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/bin/nucypher", line 11, in <module>
load_entry_point('nucypher', 'console_scripts', 'nucypher')()
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 764, in __call__
return self.main(*args, **kwargs)
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 717, in main
rv = self.invoke(ctx)
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 956, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 555, in invoke
return callback(*args, **kwargs)
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/decorators.py", line 64, in new_func
return ctx.invoke(f, obj, *args, **kwargs)
File "/home/ubuntu/.local/share/virtualenvs/nucypher-fvStivKV/lib/python3.6/site-packages/click/core.py", line 555, in invoke
return callback(*args, **kwargs)
File "/home/ubuntu/nucypher/nucypher/cli/config.py", line 219, in wrapper
return func(config, *args, **kwargs)
File "/home/ubuntu/nucypher/nucypher/cli/characters/ursula.py", line 268, in ursula
client_password=client_password)
File "/home/ubuntu/nucypher/nucypher/cli/actions.py", line 288, in make_cli_character
**config_args)
File "/home/ubuntu/nucypher/nucypher/config/node.py", line 215, in __call__
return self.produce(**character_kwargs)
File "/home/ubuntu/nucypher/nucypher/config/characters.py", line 103, in produce
merged_parameters = self.generate_parameters(**overrides)
File "/home/ubuntu/nucypher/nucypher/config/node.py", line 284, in generate_parameters
merged_parameters = {**self.static_payload(), **self.dynamic_payload, **overrides}
File "/home/ubuntu/nucypher/nucypher/config/characters.py", line 98, in dynamic_payload
return {**super().dynamic_payload, **payload}
File "/home/ubuntu/nucypher/nucypher/config/node.py", line 385, in dynamic_payload
self.read_known_nodes()   # Requires a connected blockchain to init Ursulas.
File "/home/ubuntu/nucypher/nucypher/config/node.py", line 260, in read_known_nodes
known_nodes = self.node_storage.all(federated_only=self.federated_only)
File "/home/ubuntu/nucypher/nucypher/config/storages.py", line 415, in all
federated_only=federated_only)  # TODO: 466
File "/home/ubuntu/nucypher/nucypher/config/storages.py", line 384, in __read_metadata
node = Ursula.from_bytes(node_bytes, registry=registry, federated_only=federated_only)
File "/home/ubuntu/nucypher/nucypher/characters/lawful.py", line 1175, in from_bytes
ursula = cls.from_public_keys(registry=registry, federated_only=federated_only, **node_info)
File "/home/ubuntu/nucypher/nucypher/characters/base.py", line 310, in from_public_keys
return cls(is_me=False, federated_only=federated_only, crypto_power=crypto_power, *args, **kwargs)
File "/home/ubuntu/nucypher/nucypher/characters/lawful.py", line 831, in __init__
**character_kwargs)
File "/home/ubuntu/nucypher/nucypher/characters/base.py", line 116, in __init__
raise ValueError(f"Pass either federated only or registry.  Got '{federated_only}'. '{registry}'")
ValueError: Pass either federated only or registry.  Got 'None'. 'None'
Sentry is attempting to send 0 pending error messages
Waiting up to 2.0 seconds
Press Ctrl-C to quit

# Fixed code
def remember_node(self, node, force_verification_check=False, record_fleet_state=True):
    if node == self:  # No need to remember self.
        return False

    # First, determine if this is an outdated representation of an already known node.
    # TODO: #1032
    with suppress(KeyError):
        already_known_node = self.known_nodes[node.checksum_address]
        if not node.timestamp > already_known_node.timestamp:
            self.log.debug("Skipping already known node {}".format(already_known_node))
            # This node is already known.  We can safely return.
            return False

    try:
        stranger_certificate = node.certificate
    except AttributeError:
        # Whoops, we got an Alice, Bob, or someone...
        raise self.NotATeacher(
            f"{node.__class__.__name__} does not have a certificate and cannot be remembered."
        )

    # Store node's certificate - It has been seen.
    certificate_filepath = self.node_storage.store_node_certificate(
        certificate=stranger_certificate
    )

    # In some cases (seed nodes or other temp stored certs),
    # this will update the filepath from the temp location to this one.
    node.certificate_filepath = certificate_filepath
    self.log.info(f"Saved TLS certificate for {node.nickname}: {certificate_filepath}")

    try:
        node.verify_node(
            force=force_verification_check,
            network_middleware=self.network_middleware,
            registry=self.registry,
        )  # composed on character subclass
    except SSLError:
        return False  # TODO: Bucket this node as having bad TLS info - maybe it's an update that hasn't fully propagated?

    except NodeSeemsToBeDown:
        self.log.info(
            "No Response while trying to verify node {}|{}".format(
                node.rest_interface, node
            )
        )
        return False  # TODO: Bucket this node as "ghost" or something: somebody else knows about it, but we can't get to it.

    listeners = self._learning_listeners.pop(node.checksum_address, tuple())
    address = node.checksum_address

    self.known_nodes[address] = node

    if self.save_metadata:
        self.node_storage.store_node_metadata(node=node)

    self.log.info(
        "Remembering {} ({}), popping {} listeners.".format(
            node.nickname, node.checksum_address, len(listeners)
        )
    )
    for listener in listeners:
        listener.add(address)
    self._node_ids_to_learn_about_immediately.discard(address)

    if record_fleet_state:
        self.known_nodes.record_fleet_state()

    return node