How to parse this line of code manually

[Davy]

On Aug 28, 11:00 am, Davy <zhushe... at gmail.com> wrote:
> Hi all,
>
> It is well known that Python is appreciated for its merit of concise.
> However, I found the over concise code is too hard to understand for
> me.
>
> Consider, for instance,
> def known_edits2(word):
>     return set(e2 for e1 in edits1(word) for e2 in edits1(e1) if e2 in
> NWORDS)
>
> Shall I understand the code in set() as
> for e2 in edits1(e1) {
>     if e2 in NWORDS {
>         for e1 in edits1(word) {
>              e2
>         }
>     }
>
> }
>
[SNIP]
Hi all, I figured it myself. It is left to righ parse, right?
So the above one is like
for e1 in edits1(word) {
    for e2 in edits1(e1) {
        if e2 in NWORDS {
            push e2 to set
        }
    }
}
> And a general question is: Is there any tip available to understand
> the code in one line, or what's the parsing priority (left to right,
> right to left, or other possibilities)
>
> Any suggestions are welcome!
>
> The code is a simple spell checker fromhttp://www.norvig.com/spell-correct.html
>
> Best regards,
> Davy