where to put the external ID for the custom module I'm using the modul_custom folder with __init__ py and Raihan_purchase folder with __init__ py where inside the folder there are models, security, and views folder.

CSV file is:

id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
access_Raihan_purchase,access_Raihan_purchase,model_Raihan_purchase,,1,1,1,1