python - One of my models causes the ...has no attribute '_meta' error when registered to the Admin interface. -

my project consists of 'user' model , 'timer' model.

my timer model looks this:

class usertimer(models.model):     timer_user = models.foreignkey('reguser', related_name='user', verbose_name="user", null=true)     timer_ispresent = models.booleanfield(_("user present?"), default=false, blank=true)     timer_entertime = models.timefield(blank=true, null=true, editable=false)     timer_exittime = models.timefield(blank=true, null=true, editable=false)      class meta:         verbose_name = _('timer')      def timerin(self, user):         ...         return 

after registering users model, in same way trying register timer model too:

class timeradmin(admin.stackedinline):     fieldsets = ['timer_ispresent']  admin.site.register(usertimer, timeradmin) 

but attributeerror: 'nonetype' object has no attribute '_meta' error.

i realize issue me using foreignkey in timer, not sure why or how can fixed.

any appreciated.

as can see here

fieldsets list of two-tuples, in each two-tuple represents on admin form page. (a “section” of form.)

the two-tuples in format (name, field_options), name string representing title of fieldset , field_options dictionary of information fieldset, including list of fields displayed in it.

so

fieldsets = ['timer_ispresent'] 

is not enough.

and, daniel roseman has pointed out, class should not inherit stackedinline.

so put together:

class timeradmin(admin.modeladmin):     fieldsets = (             (none, {                 'fields': ('timer_ispresent', )             }),         )