Google Colab

The file has been corrupted or is not a valid notebook file.
SyntaxError: No number after minus sign in JSON at position 1 (line 1 column 2)
CustomError: SyntaxError: No number after minus sign in JSON at position 1 (line 1 column 2)
    at new oM (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:2449:164)
    at ua.program_ (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:2432:514)
    at ya (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:16:57)
    at ua.next_ (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:14:195)
    at kaa.next (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:17:48)
    at b (https://ssl.gstatic.com/colaboratory-static/common/8f8a028fad0fa8abbc0689c7520a5a43/external_binary.js:17:309)