Retrieving the raw file from a changeset using the REST API

 I have built a small python program for playing around with defects. I am able to pull the changeset collection from  a defect and view the JSON file from the changeset:

  \"modifiedBy\": {
    \"uri\": \"itemOid\\\/com.ibm.team.repository.Contributor\\\/_-jH3wEslEeWIwpv-V-YAdQ\",
    \"itemId\": \"_-jH3wEslEeWIwpv-V-YAdQ\",
    \"com.ibm.team.repository.typeName\": \"com.ibm.team.repository.Contributor\"
  },
  \"changes\": [
    {
      \"item\": {
        \"uri\": \"itemOid\\\/com.ibm.team.filesystem.FileItem\\\/__5o0cB46EeSVP4AOyaueFQ\",
        \"itemId\": \"__5o0cB46EeSVP4AOyaueFQ\",
        \"com.ibm.team.repository.typeName\": \"com.ibm.team.filesystem.FileItem\"
      },
      \"kind\": 2,
      \"internalId\": \"_BoAmYKQNEeW8tvYITYLrgw\",
      \"merges\": [
        {
          \"state\": \"_RSx_xKNVEeW8tvYITYLrgw\",
          \"kind\": 2,
          \"internalId\": \"_Eu--YKQNEeW8tvYITYLrgw\"
        },
        {
          \"state\": \"_uhcTxPTpEeWwxYsnqAeZMw\",
          \"kind\": 2,
          \"internalId\": \"_RHgJoPWjEeWwxYsnqAeZMw\"
        }
      ],
      \"after\": \"_QvOzlPWjEeWwxYsnqAeZMw\",
      \"before\": \"_Fo6TSI4YEeWx7vJbV417Gw\"
    }
  ],
  \"originalSourceType\": 0,
  \"active\": false,
  \"originalSourceId\": null,
  \"modified\": \"2016-03-29T14: 17: 55.200Z\",
  \"predecessor\": \"_RHgJofWjEeWwxYsnqAeZMw\",
  \"contextId\": \"_Dp6kMdwTEd2jUupDpQV1Rw\",
  \"uri\": \"itemOid\\\/com.ibm.team.scm.ChangeSet\\\/_BkszsKQNEeW8tvYITYLrgw\",
  \"stateId\": \"_B7kI-fW5EeWwxYsnqAeZMw\",
  \"itemId\": \"_BkszsKQNEeW8tvYITYLrgw\",
  \"mergePredecessor\": null,
  \"properties\": [
    
  ],
  \"lastUpdatedDate\": \"2016-03-29T14: 17: 55.152Z\",
  \"owner\": {
    \"uri\": \"itemOid\\\/com.ibm.team.repository.Contributor\\\/_-jH3wEslEeWIwpv-V-YAdQ\",
    \"itemId\": \"_-jH3wEslEeWIwpv-V-YAdQ\",
    \"com.ibm.team.repository.typeName\": \"com.ibm.team.repository.Contributor\"
  },
  \"sourceType\": 0,
  \"etag\": \"_B7kI-fW5EeWwxYsnqAeZMw\",
  \"sourceId\": null,
  \"component\": {
    \"uri\": \"itemOid\\\/com.ibm.team.scm.Component\\\/_ouBTQE53EeCaGOtM6Ru5Tg\",
    \"itemId\": \"_ouBTQE53EeCaGOtM6Ru5Tg\",
    \"com.ibm.team.repository.typeName\": \"com.ibm.team.scm.Component\"
  },
  \"xComponentLink\": null,
  \"comment\": \"Merges 10.1 pom changes with current development\",
  \"com.ibm.team.repository.typeName\": \"com.ibm.team.scm.ChangeSet\"
}"

Now, I want to pull a copy of the file from this json file. What is the URL I need to compose to get the file? 

Thanks.