How to update custom field type Object(IPaddress) in Prefix using a script?

[el-magneto]

Hi!
Can you help me with saving following changes on updated prefix object?
I've created a custom field of Type Object(IPaddress) in Prefix object called "default_gateway"
Now I need to set gateways for prefixes like below, but I dont know how to save it...

### NetBox interactive shell (NETBOX2)
### Python 3.8.10 | Django 4.2.11 | NetBox 3.7.4
### lsmodels() will show available models. Use help(<model>) for more info.
>>>
>>> from extras.scripts import *
>>> from ipam.models import *
>>> from dcim.models import *
>>> from extras.models import *
>>> item = ["192.168.99.0/24","192.168.99.1/24"]
>>> prefix =  Prefix.objects.get(prefix=item[0])
>>> prefix
<Prefix: 192.168.99.0/24>
>>> gw =  IPAddress.objects.get(address=item[1])
>>> gw
<IPAddress: 192.168.99.1/24>
>>> prefix.custom_field_data['default_gateway'] = gw
>>> prefix.custom_field_data
{'default_gateway': <IPAddress: 192.168.99.1/24>}
>>> prefix.save()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/opt/netbox-3.7.4/netbox/ipam/models/ip.py", line 338, in save
    super().save(*args, **kwargs)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/base.py", line 814, in save
    self.save_base(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/base.py", line 877, in save_base
    updated = self._save_table(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/base.py", line 990, in _save_table
    updated = self._do_update(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/base.py", line 1054, in _do_update
    return filtered._update(values) > 0
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/query.py", line 1231, in _update
    return query.get_compiler(self.db).execute_sql(CURSOR)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1984, in execute_sql
    cursor = super().execute_sql(result_type)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1562, in execute_sql
    cursor.execute(sql, params)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 67, in execute
    return self._execute_with_wrappers(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/cursor.py", line 728, in execute
    self._conn.wait(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/connection.py", line 969, in wait
    return waiting.wait(gen, self.pgconn.socket, timeout=timeout)
  File "psycopg_binary/_psycopg/waiting.pyx", line 190, in psycopg_binary._psycopg.wait_c
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/cursor.py", line 210, in _execute_gen
    pgq = self._convert_query(query, params)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/client_cursor.py", line 79, in _convert_query
    pgq.convert(query, params)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/_queries.py", line 213, in convert
    self.dump(vars)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/_queries.py", line 223, in dump
    self.params = tuple(
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/_queries.py", line 224, in <genexpr>
    self._tx.as_literal(p) if p is not None else b"NULL" for p in params
  File "psycopg_binary/_psycopg/transform.pyx", line 206, in psycopg_binary._psycopg.Transformer.as_literal
  File "psycopg_binary/_psycopg/transform.pyx", line 215, in psycopg_binary._psycopg.Transformer.as_literal
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/adapt.py", line 57, in quote
    value = self.dump(obj)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/psycopg/types/json.py", line 151, in dump
    data = dumps(obj)
  File "/usr/lib/python3.8/json/__init__.py", line 234, in dumps
    return cls(
  File "/usr/lib/python3.8/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.8/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/opt/netbox-3.7.4/netbox/utilities/json.py", line 17, in default
    return super().default(o)
  File "/opt/netbox-3.7.4/venv/lib/python3.8/site-packages/django/core/serializers/json.py", line 106, in default
    return super().default(o)
  File "/usr/lib/python3.8/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type IPAddress is not JSON serializable

[candlerb]

I don't have existing data to check this against, but try using the numeric ID of the object, i.e.

prefix.custom_field_data['default_gateway'] = gw.pk

[el-magneto]

Awesome. It works! Thanks!
Should I use:

prefix.full_clean()
prefix.save()

or
prefix.save()
is enough?

[candlerb]

Always do a full_clean() before save().

If you want change logging to work, you also need to do a snapshot() after loading the object and before making the first modification to it.