Function on_change to count selected and unselected boolean fields and display how many fields are selected and how many fields are unselected

Alfa y Omega Pachuca

Hi, in this particular case i have 10 boolean fields, the user can select all fields or just some ones, every time when the user select or unselect a field, the function must increment or decrement the value of two fields type integer (selected fields: and unselect fields). When i create a new record in my form all the fields are unselected; selected field must display: 0, unselected fields must display: 10. i am using on_change and a function but i can't install the module i get the error: AttributeError: 'int' object has no attribute 'id' and i can't continue.

Thank you :-)