code: public BoxRequestsFile.DeleteFileVersion getDeleteVersionRequest(String id, String versionId) {
          BoxRequestsFile.DeleteFileVersion request = new BoxRequestsFile.DeleteFileVersion(versionId, getDeleteFileVersionUrl(id, versionId), mSession);
          return request;
      }
docs: Gets a request that deletes a version of a file
  
  @param id    id of the file to delete a version of
  @param versionId id of the file version to delete
  @return  request to delete a file version