Installed Anaconda3, environment variables are configured, IDLE perform all no problem, but with the command-line invocation py files have a problem, is mainly the following two questions:
1. I am using jupyter notebook program, perform no problem, it is a very simple "Hello World" on the print statements

Save for py files, as follows:

At this time inside execution_count: NULL error, said the name 'NULL' not defined

2. Question 2, I will be in the py execution_count: NULL to 1, in an attempt to avoid NULL error (checked only None of python is not NULL, although I don't know why is this case), the results program execution does not return "Hello World", I want no error


Your advice please!