Hello everyone, I am currently migrating a report module to odoo 16 but I am encountering an error not in the installation but when trying to view the report, the error is as follows: 

Traceback (most recent call last):
  File "/odoo/odoo-server/odoo/models.py", line 5112, in ensure_one
    _id, = self._ids
ValueError: not enough values to unpack (expected 1, got 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/odoo/odoo-server/odoo/models.py", line 5112, in ensure_one
_id, = self._ids
ValueError: not enough values to unpack (expected 1, got 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/odoo/odoo-server/odoo/http.py", line 1579, in _serve_db
return service_model.retrying(self._serve_ir_http, self.env)
File "/odoo/odoo-server/odoo/service/model.py", line 134, in retrying
result = func()
File "/odoo/odoo-server/odoo/http.py", line 1608, in _serve_ir_http
response = self.dispatcher.dispatch(rule.endpoint, args)
File "/odoo/odoo-server/odoo/http.py", line 1805, in dispatch
result = self.request.registry['ir.http']._dispatch(endpoint)
File "/odoo/odoo-server/odoo/addons/base/models/ir_http.py", line 144, in _dispatch
result = endpoint(**request.params)
File "/odoo/odoo-server/odoo/http.py", line 698, in route_wrapper
result = endpoint(self, *args, **params_ok)
File "/odoo/odoo-server/addons/web/controllers/dataset.py", line 42, in call_kw
return self._call_kw(model, method, args, kwargs)
File "/odoo/odoo-server/addons/web/controllers/dataset.py", line 33, in _call_kw
return call_kw(request.env[model], method, args, kwargs)
File "/odoo/odoo-server/odoo/api.py", line 461, in call_kw
result = _call_kw_multi(method, model, args, kwargs)
File "/odoo/odoo-server/odoo/api.py", line 448, in _call_kw_multi
result = method(recs, *args, **kwargs)
File "/odoo/enterprise/addons/account_reports/models/account_report.py", line 3427, in get_report_informations
self.ensure_one()
File "/odoo/odoo-server/odoo/models.py", line 5115, in ensure_one
raise ValueError("Expected singleton: %s" % self)
ValueError: Expected singleton: account.report()

The above server error caused the following client error:
null

and this is my code to generate the query: 
classAccountReportSar(models.Model):
_name='account.report.sar'
_description='Reporte de libros contables SAR'
_auto=False
fecha= fields.Date(readonly=True)
empresa= fields.Char(readonly=True)
rtn= fields.Char(readonly=True)
state= fields.Selection([        
('draft', 'Unposted'), ('posted', 'Posted'), ('cancel', 'Cancelled')], 'Status', readonly=True)
factura= fields.Char(readonly=True)
no_tax_def= fields.Monetary(readonly=True, string='Sin Ind. Impuesto', currency_field='company_currency_id')isvimp= fields.Monetary(readonly=True, string='isvimp', currency_field='company_currency_id')exeimp= fields.Monetary(readonly=True, string='', currency_field='company_currency_id')isvr10= fields.Monetary(readonly=True, string='', currency_field='company_currency_id')exento= fields.Monetary(readonly=True, string='Importe Exento', currency_field='company_currency_id')exonerado= fields.Monetary(readonly=True, string='Importe Exonerado', currency_field='company_currency_id')gravado= fields.Monetary(readonly=True, currency_field='company_currency_id')gravado15= fields.Monetary(readonly=True, string='Gravado 15%', currency_field='company_currency_id')gravado18= fields.Monetary(readonly=True, string='Gravado 18%', currency_field='company_currency_id')impuesto15= fields.Monetary(readonly=True, string='Impuesto 15%', currency_field='company_currency_id')impuesto18= fields.Monetary(readonly=True, string='Impuesto 18%', currency_field='company_currency_id')impuesto= fields.Monetary(readonly=True, string='Impuesto Total', currency_field='company_currency_id')total= fields.Monetary(readonly=True, currency_field='company_currency_id')type= fields.Char(readonly=True)journal_id= fields.Many2one('account.journal', readonly=True, auto_join=True)company_id= fields.Many2one('res.company', readonly=True, auto_join=True)company_currency_id= fields.Many2one(related='company_id.currency_id', readonly=True)move_id= fields.Many2one('account.move', string='Entry', auto_join=True)
_depends= {'account.move':['id','move_type','invoice_date','name','state','journal_id','company_id','amount_total_signed','amount_total','date','currency_id','partner_id','l10n_latam_document_type_id'],'res.currency':['currency_id'],
'res.partner':['name','vat'],
'account.move.line':['id','price_subtotal','account_id','move_id'],
'account.move.line.account.tax.rel':['account_move_line_id'],
'account.tax':['id','name'],
'res.currency.rate':['rate','currency_id','name'],
'res.company':['id'],
'account.journal':['id','name']    }
definit(self):
cr=self._cr        
tools.drop_view_if_exists(cr, self._table)
query="""my query"""

sql="""CREATE or REPLACE VIEW %s as (%s)"""% (self._table, query)
cr.execute(sql)


Could you tell me what I'm doing wrong?
the code is for version 16.

Thank you in advance for your help