[15] installation fails with error non-existing model 'analytic.mixin'

[alentsch]

Module

Contracts Management - Recurring

Describe the bug

Installation of the module in Odoo 15 results in error.
Dependency problem suspected (non-existing model 'analytic.mixin')

Notes

The file 'analytic_mixin.py' is only part of the core files of 'account analytic' since Odoo 16.
https://github.com/OCA/account-analytic/blob/16.0/account_analytic_distribution_manual/models/analytic_mixin.py

To Reproduce

Affected versions: 15.0.1.13.0

Steps to reproduce the behavior:

1. Download with command $ git clone -b 15.0 https://github.com/OCA/contract.git
2. Copy 'contract' sub-folder into the '.../share/Odoo/addons/15.0/'
3. 'Update App List' > Clicking Install in 'Recurring - Contracts Management'
4. Error occursNOTE: Product Code Mixin, the dependency which appears to be missing, is only available for Odoo 16.
   https://odoo-community.org/shop/product-code-mixin-715413

Expected behavior
Expecting the installation not end with error.

Note:
Sorry, I am a user not a developer — am I doing something wrong? Short installation instruction would be very nice to have.

Complete error message

RPC_ERROR
Odoo Server Error
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_http.py", line 237, in _dispatch
    result = request.dispatch()
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 687, in dispatch
    result = self._call_function(**self.params)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 359, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 348, in checked_call
    result = self.endpoint(*a, **kw)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 910, in __call__
    return self.method(*args, **kw)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 535, in response_wrap
    response = f(*args, **kw)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 1330, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 1318, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 464, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "/usr/lib/python3/dist-packages/odoo/api.py", line 451, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "<decorator-gen-74>", line 2, in button_immediate_install
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 74, in check_and_log
    return method(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 486, 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 603, in _button_immediate_function
    registry = modules.registry.Registry.new(self._cr.dbname, update_module=True)
  File "/usr/lib/python3/dist-packages/odoo/modules/registry.py", line 87, in new
    odoo.modules.load_modules(registry, force_demo, status, update_module)
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 474, in load_modules
    processed_modules += load_marked_modules(cr, graph,
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 363, in load_marked_modules
    loaded, processed = load_module_graph(
  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 188, in load_module_graph
    model_names = registry.load(cr, package)
  File "/usr/lib/python3/dist-packages/odoo/modules/registry.py", line 237, in load
    model = cls._build_model(self, cr)
  File "/usr/lib/python3/dist-packages/odoo/models.py", line 636, in _build_model
    raise TypeError("Model %r inherits from non-existing model %r." % (name, parent))
Exception

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 643, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 301, in _handle_exception
    raise exception.with_traceback(None) from new_cause
TypeError: Model 'contract.line' inherits from non-existing model 'analytic.mixin'.