gallery stack trace

Traceback (most recent call last):
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/staticfiles/handlers.py", line 65, in __call__
    return self.application(environ, start_response)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/wsgi.py", line 141, in __call__
    response = self.get_response(request)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/base.py", line 75, in get_response
    response = self._middleware_chain(request)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/exception.py", line 36, in inner
    response = response_for_exception(request, exc)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/exception.py", line 90, in response_for_exception
    response = handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info())
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/exception.py", line 125, in handle_uncaught_exception
    return debug.technical_500_response(request, *exc_info)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django_extensions/management/technical_response.py", line 37, in null_technical_500_response
    six.reraise(exc_type, exc_value, tb)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/six.py", line 702, in reraise
    raise value.with_traceback(tb)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/utils/decorators.py", line 142, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/sites.py", line 223, in inner
    return view(request, *args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/views/decorators/clickjacking.py", line 33, in wrapped_view
    resp = view_func(*args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/cms/admin/placeholderadmin.py", line 344, in add_plugin
    response = plugin_instance.add_view(request)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/options.py", line 1645, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/utils/decorators.py", line 45, in _wrapper
    return bound_method(*args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/utils/decorators.py", line 142, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/options.py", line 1529, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/options.py", line 1573, in _changeform_view
    self.save_related(request, form, formsets, not add)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/options.py", line 1116, in save_related
    self.save_formset(request, form, formset, change=change)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/contrib/admin/options.py", line 1104, in save_formset
    formset.save()
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/forms/models.py", line 669, in save
    return self.save_existing_objects(commit) + self.save_new_objects(commit)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/forms/models.py", line 807, in save_new_objects
    self.new_objects.append(self.save_new(form, commit=commit))
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/adminsortable2/admin.py", line 455, in save_new
    obj.save()
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/base.py", line 741, in save
    force_update=force_update, update_fields=update_fields)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/base.py", line 779, in save_base
    force_update, using, update_fields,
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/base.py", line 870, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/base.py", line 908, in _do_insert
    using=using, raw=raw)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/query.py", line 1186, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1374, in execute_sql
    for sql, params in self.as_sql():
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1318, in as_sql
    for obj in self.query.objs
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1318, in <listcomp>
    for obj in self.query.objs
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1317, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1258, in prepare_value
    value = field.get_db_prep_save(value, connection=self.connection)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 793, in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 788, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/jsonfield/fields.py", line 64, in get_prep_value
    return json.dumps(value, **self.dump_kwargs)
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 201, in encode
    chunks = list(chunks)
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 431, in _iterencode
    yield from _iterencode_dict(o, _current_indent_level)
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 438, in _iterencode
    o = _default(o)
  File "/Users/mohi/.local/share/virtualenvs/weltladen-shop-HCPwLesS/lib/python3.7/site-packages/jsonfield/encoder.py", line 59, in default
    return super().default(obj)
  File "/usr/local/Cellar/python/3.7.7/Frameworks/Python.framework/Versions/3.7/lib/python3.7/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type WeltladenProduct is not JSON serializable