Google Colab

The file has been corrupted or is not a valid notebook file.
SyntaxError: Unexpected end of JSON input
CustomError: SyntaxError: Unexpected end of JSON input
    at new gM (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:2434:164)
    at va.program_ (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:2417:514)
    at ya (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:16:57)
    at va.next_ (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:14:195)
    at kaa.next (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:17:48)
    at b (https://ssl.gstatic.com/colaboratory-static/common/c2e3d6947e85eb6d757b5a34be9eada1/external_binary.js:17:309)