Odoo 10 - Error occurred when marking MO as done

Question

When I entered the analytic account in Work Center then try to mark the related manufacturing order as done this error occurred

Traceback (most recent call last):
File "/odoo/odoo-server/odoo/http.py", line 638, in _handle_exception 
 return super(JsonRequest, self)._handle_exception(exception)  
File "/odoo/odoo-server/odoo/http.py", line 675, in dispatch    
    result = self._call_function(**self.params)  
File "/odoo/odoo-server/odoo/http.py", line 331, in _call_function    
    return checked_call(self.db, *args, **kwargs)  
File "/odoo/odoo-server/odoo/service/model.py", line 119, in wrapper    
    return f(dbname, *args, **kwargs)  
File "/odoo/odoo-server/odoo/http.py", line 324, in checked_call    
    result = self.endpoint(*a, **kw)  
File "/odoo/odoo-server/odoo/http.py", line 933, in __call__    
    return self.method(*args, **kw)  
File "/odoo/odoo-server/odoo/http.py", line 504, in response_wrap    
    response = f(*args, **kw)  
File "/odoo/odoo-server/addons/web/controllers/main.py", line 866, in call_button    
    action = self._call_kw(model, method, args, {})  
File "/odoo/odoo-server/addons/web/controllers/main.py", line 854, in _call_kw    
    return call_kw(request.env[model], method, args, kwargs)  
File "/odoo/odoo-server/odoo/api.py", line 681, in call_kw    
    return call_kw_multi(method, model, args, kwargs)  
File "/odoo/odoo-server/odoo/api.py", line 672, in call_kw_multi    
    result = method(recs, *args, **kwargs)  
File "/odoo/enterprise/addons/mrp_account/models/mrp_production.py", line 63, in button_mark_done    
    self._costs_generate()  
File "/odoo/enterprise/addons/mrp_account/models/mrp_production.py", line 43, in _costs_generate    
    value = wc_line.hour * wc.costs_hourAttributeError: 'mrp.workorder' object has no attribute 'hour'

Can anyone help me how to fix it

Thanks in advance