Assignment of Name Space

At the end of callout add callout class into namespace shown below  

MPC.TestClass = TestClass; 

If you want to add callout class in separate object within MPC, then you can declare as below 

MPC.Model = MPC.Model || {}; 

MPC.Model.TestClass=TestClass; 

MPC refer to Model Prefix Code 

 

Basically this namespace you have to set in  

WINDOW -> Table & Column, TAB-> AD_Column, FIELD-> Callout Code, how to bind callout to a column that you can read from related section Bind Callout To Column.