Use only "import datetime" in tutorials to minimise confusion

[John Shaffer <jshaffer2112@…>]

#4037, #4246, #4876, #4935 were all opened because of confusion over which datetime import to use. The tutorial's model files use "import datetime", while the command-line examples use "from datetime import datetime". I propose normalizing the imports to minimize confusion.

[Simon G. <dev@…>]

Good idea.

[Malcolm Tredinnick]

(In [5871]) Fixed #4941 -- Changed imports for interactive portion of the example to be consistent with the source code file, at the expense of slightly more typing required. This might help reduce some confusion. Thanks, John Shaffer.

[Fumassump]

Here i find some
​http://index.euuerto.cn
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Good day!

[Ramiro Morales]

undo vandalism