In my odoo app i have an Area model and a Department model. Every area has a department (Many2One relation). Every department has a code and name. I wanted to overwrite the "_name_search" function in department so it can me searched using both code and name. But when I am on the Area form view and I start typing in the department_id field for selecting a department on that area, Odoo shows an error

psycopg2.ProgrammingError: operator does not exist: integer = record
LINE 1: ...OM "cusaf_department" WHERE "cusaf_department".id IN ((1, 'A...
                                                             ^
HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.

I am working with Odoo14. Here is my code:

    class Department(models.Model):
        _name = 'cusaf.department'
        _description = 'Departamento'
        name = fields.Char(string='Departamento', required=True)
        department_code = fields.Char(string='Código departamento')
        _sql_constraints = [
            ('name_uniq', 'unique (name)',
             "Error: Ya existe un departamento con el mismo nombre"),
            ('name_uniq', 'unique (department_code)',
             "Error: Ya existe un departamento con el mismo código")
        ]
        @api.model
        def _name_search(self, name='', args=None, operator='ilike', limit=100):
            if args is None:
                args = []
            domain = args + ['|', ('department_code', operator, name), ('name', operator, name)]
            return super(Department, self).search(domain, limit=limit).name_get()
class Area(models.Model):
    _name = 'cusaf.area'
    _description = 'Area'
    _inherit = ['mail.thread', 'mail.activity.mixin']
    active = fields.Boolean(default=True)
    name = fields.Char(string='Identificador externo', required=True)
    department_id = fields.Many2one('cusaf.department', string='Departamento')

And here is the full error code:

Odoo Server Error
Traceback (most recent call last):
  File "/home/ernesto/Programming/odoo/odoo14/odoo/addons/base/models/ir_http.py", line 237, in _dispatch
    result = request.dispatch()
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 683, in dispatch
    result = self._call_function(**self.params)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 359, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 347, in checked_call
    result = self.endpoint(*a, **kw)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 912, in __call__
    return self.method(*args, **kw)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 531, in response_wrap
    response = f(*args, **kw)
  File "/home/ernesto/Programming/odoo/odoo14/addons/web/controllers/main.py", line 1377, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/addons/web/controllers/main.py", line 1369, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/api.py", line 392, in call_kw
    result = _call_kw_model(method, model, args, kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/api.py", line 365, in _call_kw_model
    result = method(recs, *args, **kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/models.py", line 1792, in name_search
    return self.browse(ids).sudo().name_get()
  File "/home/ernesto/Programming/odoo/odoo14/odoo/models.py", line 1737, in name_get
    result.append((record.id, convert(record[name], record)))
  File "/home/ernesto/Programming/odoo/odoo14/odoo/models.py", line 5659, in __getitem__
    return self._fields[key].__get__(self, type(self))
  File "/home/ernesto/Programming/odoo/odoo14/odoo/fields.py", line 976, in __get__
    recs._fetch_field(self)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/models.py", line 3067, in _fetch_field
    self._read(fnames)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/models.py", line 3134, in _read
    cr.execute(query_str, params + [sub_ids])
  File "", line 2, in execute
  File "/home/ernesto/Programming/odoo/odoo14/odoo/sql_db.py", line 101, in check
    return f(self, *args, **kwargs)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/sql_db.py", line 298, in execute
    res = self._obj.execute(query, params)
Exception
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 639, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/ernesto/Programming/odoo/odoo14/odoo/http.py", line 315, in _handle_exception
    raise exception.with_traceback(None) from new_cause
psycopg2.ProgrammingError: operator does not exist: integer = record
LINE 1: ...OM "cusaf_department" WHERE "cusaf_department".id IN ((1, 'A...
                                                             ^
HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.