I have been looking over the Python documentation for code formatting best practice for large lists and dictionaries, for example,

something = {'foo' : 'bar', 'foo2' : 'bar2', 'foo3' : 'bar3'..... 200 chars wide, etc..}

or

something = {'foo' : 'bar','foo2' : 'bar2','foo3' : 'bar3',...}

or

something = {'foo' : 'bar','foo2' : 'bar2','foo3' : 'bar3',...}

How do I handle deep nesting of lists/dictionaries?

According to the PEP8 style guide there are two ways to format a dictionary:

mydict = {'key': 'value','key': 'value',...}

OR

mydict = {'key': 'value','key': 'value',...
}

If you want to conform to PEP8 I would say anything else is technically wrong.