Hi!

This is my first post here. I'm newbie with Odoo, but I'm trying to learn more about it.

I'm writing my first module. I put this piece of code into my class:

        def _get_days(self,cr,uid,ids,field_name, arg ,context=None):
            res = {},
            fmt = '%d-%m-%Y',
            for obj in self.browse(cr, uid, ids, context=context):
                #res[obj.id] = {'diff_days':0, }, #valore di default
                from_date = obj.data_inizio,
                to_date = obj.data_fine,
                d1 = datetime.strptime(from_date, fmt),
                d2 = datetime.strptime(to_date, fmt),
                daysDiff = str((d2-d1).days),
                res[obj.id]['diff_days'] = daysDiff,
            return res 

I've declared 'data_inizio', 'data_fine' and 'diff_days' in this way:

        _columns = {

            'data_inizio': fields.date('Data Inizio', required=True),
            'data_fine': fields.date('Data Fine', required=True), 
            'diff_days': fields.function(_get_days, string='Diff days', multi='sums', store=True),


            }

I've followed the instructions of this post: https://www.odoo.com/fr_FR/forum/help-1/question/how-to-calculate-difference-bitween-two-dates-31486

When I try to create a new input, I get this error:

Odoo

Odoo Server Error

Traceback (most recent call last):
  File "/home/Odoo/openerp/openerp/http.py", line 530, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/Odoo/openerp/openerp/http.py", line 567, in dispatch
    result = self._call_function(**self.params)
  File "/home/Odoo/openerp/openerp/http.py", line 303, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/service/model.py", line 113, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/http.py", line 300, in checked_call
    return self.endpoint(*a, **kw)
  File "/home/Odoo/openerp/openerp/http.py", line 796, in __call__
    return self.method(*args, **kw)
  File "/home/Odoo/openerp/openerp/http.py", line 396, in response_wrap
    response = f(*args, **kw)
  File "/home/Odoo/openerp/openerp/addons/web/controllers/main.py", line 949, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/home/Odoo/openerp/openerp/addons/web/controllers/main.py", line 941, in _call_kw
    return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/api.py", line 241, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/api.py", line 336, in old_api
    result = method(recs, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/models.py", line 4025, in create
    record = self.browse(self._create(old_vals))
  File "/home/Odoo/openerp/openerp/api.py", line 239, in wrapper
    return new_api(self, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/api.py", line 462, in new_api
    result = method(self._model, cr, uid, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/models.py", line 4226, in _create
    self.pool[model_name]._store_set_values(cr, user, ids, fields2, context)
  File "/home/Odoo/openerp/openerp/api.py", line 241, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/Odoo/openerp/openerp/models.py", line 4335, in _store_set_values
    result = self._columns[val[0]].get(cr, self, ids, val, SUPERUSER_ID, context=context)
  File "/home/Odoo/openerp/openerp/osv/fields.py", line 1361, in get
    result = self._fnct(obj, cr, uid, ids, name, self._arg, context)
  File "/home/Odoo/openerp/openerp/addons/mymodule/mymodule.py", line 28, in _get_days
    d1 = datetime.strptime(from_date, fmt),
TypeError: must be string, not tuple 

Could anyone hel me?

Thanks in advance.