why no google drive files listed in drive api request
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I am trying to get a list of file in my google drive using desktop app, the code is as follows:
def main(argv):

  storage = Storage('drive.dat')
  credentials = storage.get()

  if credentials is None or credentials.invalid:
    credentials = run(FLOW, storage)

  # Create an httplib2.Http object to handle our HTTP requests and authorize it
  # with our good Credentials.
  http = httplib2.Http()
  http = credentials.authorize(http)

  service = build("drive", "v2", http=http)
  retrieve_all_files(service)
Then in retrieve_all_files. I print the files:
     param = {}
      if page_token:
        param['pageToken'] = page_token
      files = service.files().list(**param).execute()
      print files
The thing is after I authenticate the access to my account, the printed file list has no items. Does anyone have similar problem or is there a solution to this?
Thank you very much
