Apache Atlas many to many relationship between entities

Question

I am trying to set up a data cataloging system using Apache Atlas, and I need to create many-to-many relationships between entities. Specifically, I want to establish a relationship between two entities where each entity can have multiple instances of the other entity.

this is the relationship def that I created

{
   "name":"subscribe",
   "typeName":"subscribe",
   "description":"Client provided by the application",
   "category":"RELATIONSHIP",
   "typeVersion":"1.0",
   "relationshipCategory":"ASSOCIATION",
   "propagateTags":"NONE",
   "endDef1":{
      "name":"application",
      "type":"client",
      "cardinality":"SET",
      "isContainer":false,
      "isLegacyAttribute":false
   },
   "endDef2":{
      "name":"client",
      "type":"application",
      "cardinality":"SET",
      "isContainer":false,
      "isLegacyAttribute":false
   }
}

and this is the json object that i used to create entity,

{
   "entity":{
      "typeName":"service",
      "attributes":"attributes",
      "relationshipAttributes":{
         "application":{
            "typeName":"application",
            "uniqueAttributes":{
               "id":application_id
            }
         }
      }
   }
}

but while creating the relationships using the apache-atlas python client, I'm getting the below mentioned error

errorMessage': 'Relationship end is invalid. Expected application but is NULL

Can someone provide an example of how to create many-to-many relationships in Apache Atlas, or point me in the direction of some documentation or tutorials that can help? I would greatly appreciate any assistance you can provide. Thank you!