must be str not int

[auting82]

Please show full error traceback, it contains important information.

Hi again. Tested my code this morning in python and I kid you not I am able to generate a graph. However it is not correct as shown in the book I am learning from .
Here is what I get: https://www.imageupload.co.uk/image/DId1
And here is what I should be getting: https://www.imageupload.co.uk/image/DIdg