def ldap_modify(user_list, attribute, new_value):
    ldif = [(ldap.MOD_REPLACE, attribute, new_value)]
    for user in user_list:
        dn="cn={}, ou=users, DC=example, DC=co, DC=uk".format(user)
        l.modify_s(dn, ldif)

user_list = ['Test User', 'Test User2', ...] # i.e. list of users full names
attribute = 'description'
new_value = 'test'

ldap.NO_SUCH_OBJECT: {'info': '00002030: No such Base DN: sAMAccountName=testuser1, ou=users, DC=example, DC=co, DC=uk', 'desc': 'No such object'}