This script is intended to create simple group without nested groups as some application can't handle nested groups in LDAP.

add_nested_group_members.py

import ldap
from ldap import modlist

ldap_connection = 'ldap://<ip>:<port>'
domain = 'dc=<your domain>'
admin = 'cn=admin,%s' % domain
password = '<secret>'

simple_group = 'cn=<group that needs members>,ou=Groups,%s' % domain
top_group = 'cn=<top group>,ou=Groups,%s' % domain

# Initialize LDAP connection and Bind admin to it
conn = ldap.initialize(ldap_connection)
conn.bind_s(admin, password, ldap.AUTH_SIMPLE)

# Initialize first group and person list
groups = [top_group]
person = []

# Traverse the tree of groups and users
for group in groups:
    membersof = conn.search_s(group, ldap.SCOPE_SUBTREE, attrlist=['member'])
    for item in membersof:
        for member in item[1]['member']:
            isgroup = len(conn.search_s(member, ldap.SCOPE_BASE, 'objectClass=groupOfNames'))
            isperson = len(conn.search_s(member, ldap.SCOPE_BASE, 'objectClass=person'))
            if isgroup:
                groups.append(member)
            if isperson:
                person.append(member)

# Create an LDIF object
old_attribute = conn.search_s(simple_group, ldap.SCOPE_SUBTREE, attrlist=['member'])
old = old_attribute[0][1]
new = {'member': set(person)}
ldif = modlist.modifyModlist(old,new)

# Modify the member attribute
conn.modify_s(simple_group, ldif)

# Unbind the admin
conn.unbind_s()