[Self-platform-dev] self_rc1-Add Course Problem

[Bijomon Baby]

Hello.....
                  When i am trying to add Course into a collection give an error called-
  string indices must be integers in line No 44
                  CODE:
                              input = {
                                           'nodetype':'object',

          'uid':uid,
                                            'nid':title,
                                            'status':'public',
                                            'attributes':[('title',title),('description',description)],
                                             'language':languageid,
                                            'relation':[ ( 'belongsto',[str(categoryid)] ) ],//this is Line No 44
                                            'instanceof':['55'] #instance of OT Courses
                                     }

                sir i am not able to undestand what error stands for...
                'str' i change to 'int' then also an error occured