Combining two JSON objects in to one

I have two JSON objects. One is python array which is converted using json,dumps() and other contains records from database and is serialized using json serializer. I want to combine them into a single JSON object.

For eg:

obj1 = ["a1", "a2", "a3"]

obj2 = [{
    "pk": "e1",
    "model": "AB.abc",
    "fields": {
      "e_desc": "abcd"
    }
  },
  {
    "pk": "e1",
    "model": "AB.abc",
    "fields": {
      "e_desc": "hij"
    }
  }
]

I want to merge them into single object as below:

finalObj = {
  obj1: ["a1", "a2", "a3"],
  obj2: [{
      "pk": "e1",
      "model": "AB.abc",
      "fields": {
        "e_desc": "abcd"
      }
    },
    {
      "pk": "e1",
      "model": "AB.abc",
      "fields": {
        "e_desc": "hij"
      }
    }
  ]
}

How can i do this?