I'm trying to install a custom module but I'm getting this error:

RPC_ERROR

Odoo Server Error

Traceback (most recent call last):

  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1584, in _serve_db

    return service_model.retrying(self._serve_ir_http, self.env)

  File "/usr/lib/python3/dist-packages/odoo/service/model.py", line 133, in retrying

    result = func()

  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1611, in _serve_ir_http

    response = self.dispatcher.dispatch(rule.endpoint, args)

  File "/usr/lib/python3/dist-packages/odoo/http.py", line 1815, 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 697, 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 74, in check_and_log

    return method(self, *args, **kwargs)

  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_module.py", line 468, 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 592, 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 488, in load_modules

    processed_modules += load_marked_modules(cr, graph,

  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 372, in load_marked_modules

    loaded, processed = load_module_graph(

  File "/usr/lib/python3/dist-packages/odoo/modules/loading.py", line 208, in load_module_graph

    registry.init_models(cr, model_names, {'module': package.name}, new_install)

  File "/usr/lib/python3/dist-packages/odoo/modules/registry.py", line 531, in init_models

    env['ir.model.fields.selection']._reflect_selections(model_names)

  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 1287, in _reflect_selections

    expected = {

  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 1291, in

    for index, (value, label) in enumerate(field.selection)

ValueError: too many values to unpack (expected 2)

The above server error caused the following client error:

RPC_ERROR: Odoo Server Error

    RPCError@http://localhost:8069/web/assets/192-39f72eb/web.assets_backend.min.js:981:274

    makeErrorFromResponse@http://localhost:8069/web/assets/192-39f72eb/web.assets_backend.min.js:985:163

    jsonrpc/promise

This is what my models.py class looks like:

# -*- coding: utf-8 -*-

from odoo import models, fields, api

class restaurante(models.Model):
    _name = 'trabajo_modulo.restaurante'
    _description = 'Define el restaurante'

    nombre = fields.Char('Nombre', required=True)
    nMesas = fields.Integer(string='Número de mesas', required=True)

class mesa(models.Model):
    _name = 'trabajo_modulo.mesa'
    _description = 'Define la mesa'

    num = fields.Integer(string='Número', required = True)
    capacidad = fields.Integer(string='Capacidad', default=4)

class empleado(models.Model):
    _name = 'trabajo_modulo.empleado'
    _description = 'Permite definir las características de un empleado'

    nombre = fields.Char('Nombre', required=True)
    nif = fields.Char('NIF', required=True)
    puesto = fields.Selection(string='Puesto', selection=[('w','Camarero'), ('c','Cocinero'), ('p', 'Repostero')], default='w')
    sueldo = fields.Float(string='Sueldo')
    fecha_incorporacion = fields.Date(string='Fecha de incorporación')
    experiencia = fields.Integer('Experiencia', compute='_get_antiguedad')

    @api.depends('fecha_incorporacion')
    def _get_antiguedad(self):
        for empleado in self:
            empleado.experiencia = 0

I thought at first it was caused by the 'puesto' line, but the error kept appearing after commenting it out.