Hello, I just bought this module and I have an issue while installing the module

I think you need to adapt correctly to the v16 version.

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 85, in lookup
    r = d[key]
  File "", line 2, in __getitem__
  File "/usr/lib/python3/dist-packages/odoo/tools/func.py", line 87, in locked
    return func(inst, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/tools/lru.py", line 34, in __getitem__
    a = self.d[obj]
KeyError: ('ir.model.data', , 'point_of_sale.assets')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 698, in _tag_root
    f(rec)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 676, in _tag_template
    return self._tag_record(record)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 568, in _tag_record
    f_val = self.id_get(f_ref, raise_if_not_found=nodeattr2bool(rec, 'forcecreate', True))
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 681, in id_get
    res = self.model_id_get(id_str, raise_if_not_found)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 687, in model_id_get
    return self.env['ir.model.data']._xmlid_to_res_model_res_id(id_str, raise_if_not_found=raise_if_not_found)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 2010, in _xmlid_to_res_model_res_id
    return self._xmlid_lookup(xmlid)[1:3]
  File "", line 2, in _xmlid_lookup
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 90, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 2003, in _xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
ValueError: External ID not found in the system: point_of_sale.assets

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1583, in _serve_db
    return service_model.retrying(self._serve_ir_http, self.env)
  File "/usr/lib/python3/dist-packages/odoo/service/model.py", line 134, in retrying
    result = func()
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1610, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1807, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_http.py", line 154, in _dispatch
    result = endpoint(**request.params)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 696, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/dataset.py", line 46, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/dataset.py", line 33, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 461, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 448, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "", line 2, in button_immediate_install
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 76, in check_and_log
    return method(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 491, in button_immediate_install
    return self._button_immediate_function(type(self).button_install)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 615, in _button_immediate_function
    registry = modules.registry.Registry.new(self._cr.dbname, update_module=True)
  File "", line 2, in new
  File "/usr/lib/python3/dist-packages/odoo/tools/func.py", line 87, in locked
    return func(inst, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/modules/registry.py", line 90, in new
    odoo.modules.load_modules(registry, force_demo, status, update_module)
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 487, in load_modules
    processed_modules += load_marked_modules(cr, graph,
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 371, in load_marked_modules
    loaded, processed = load_module_graph(
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 230, in load_module_graph
    load_data(cr, idref, mode, kind='data', package=package)
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 71, in load_data
    tools.convert_file(cr, package.name, filename, idref, mode, noupdate, kind)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 763, in convert_file
    convert_xml_import(cr, module, fp, idref, mode, noupdate)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 829, in convert_xml_import
    obj.parse(doc.getroot())
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 749, in parse
    self._tag_root(de)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 698, in _tag_root
    f(rec)
  File "/usr/lib/python3/dist-packages/odoo/tools/convert.py", line 711, in _tag_root
    raise ParseError('while parsing %s:%s, somewhere inside\n%s' % (
odoo.tools.convert.ParseError: while parsing None:4, somewhere inside

          
              
          
        

The above server error caused the following client error:
RPC_ERROR: Odoo Server Error
    at makeErrorFromResponse (http://localhost:8067/web/assets/55195-0fb172b/web.assets_backend.min.js:977:163)
    at XMLHttpRequest. (http://localhost:8067/web/assets/55195-0fb172b/web.assets_backend.min.js:985:13)