Setting local roles on dexterity content type

Development
1

I have a content type and I want to assign local roles 'Contributor','Reader' based on a field but is not working, I can't figure what's wrong
I tried:

def assignRole(self):
    deptGroup = 'cs-'+ str(self.croACAD_ORG) + '-grp'
    self.manage_setLocalRoles(deptGroup, ['Contributor','Reader'])
    self.reindexObjectSecurity()

and

def assignRole(self):
    deptGroup = 'cs-'+ str(self.croACAD_ORG) + '-grp'
    deptGroup = 'cs-grp'
    api.user.grant_roles(username=deptGroup,roles=['Contributor', 'Editor'],)
2

The usage of grant_roles() makes no sense since you did not specify the context object that should be used to apply the local roles (defaults to plone site root as documented).

3

Assigning the context did not work neither

api.group.grant_roles(groupname='deptGroup',roles=['Contributor', 'Editor'], obj=self.context)

4

this is the full file https://pastebin.com/bBPkGMKU