the FAST_MODELADMIN_MODULES

Modules Settings

control where forms and actions are taken from.
will use admin.py and forms.py files by default.
can work with a folder with an __init__.py file.

ADMIN

where actions are taken from.

FAST_MODELADMIN_MODULES = {'ADMIN': 'file.py'}
# or
FAST_MODELADMIN_MODULES = {'ADMIN': 'admin_package'}

FORMS

where forms are taken form.

FAST_MODELADMIN_MODULES = {'FORMS': 'file.py'}
# or
FAST_MODELADMIN_MODULES = {'FORMS': 'forms_package'}