1. What's the maximum level of recursion and how do I change it in Python?

2. How do I refer to the null object in Python?

3. How do a copy the contents of a list and not just a reference to the list in Python?

Q 1. What's the maximum level of recursion and how do I change it in Python?

A. The default is 1000 levels deep and you can change that using the setrecursionlimit function in the sys module.  Beware that some operating systems may start running into problems if you go much higher due to limited stack space.

Q 2. How do I refer to the null object in Python?

A Refer to None which is Python's null object. Note that it's None with a capital N!

Q 3. How do a copy the contents of a list and not just a reference to the list in Python?

A Use a slice notation.  Thus

newlist = oldlist
.... will assign a second name to the same list

newlist = oldlist[:]
....  will duplicate each element of oldlist into a complete new list called newlist

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