I perform inheritance as follows,

class trademark_file_details(osv.osv):

    _description = 'Trademark File'

    _name = 'trademark.file.details'
    
    _inherit = 'file.details'

    _columns = {
                'trademark' : fields.char('This file is', required=True),
                }
    _defaults = {
        'name': 'Trademark',
    }

trademark_file_details()

But error occured,,

    'You may need to add a dependency on the parent class\' module.' % (name, parent))
TypeError: The model "trademark.file.details" specifies an unexisting parent class "file.details"
You may need to add a dependency on the parent class' module.

ANY1 can solve it???