if price is zero then the result will be -1

Most of the solutions have used ASCII conversion but this solution hasn't. Therefore it's clever in my opinion.

very cool

Moderators can do this.

author is inactive and the kata is really old with possible duplicates

is it possible to unpublish a kata without needing the author?

Writing a bunch of if's and doing arithmetic is not a novel kata idea, and I think I've already seen an exact same kata before too.

new python test framework should be added, no?

i would replace your string in alphabet with

import string
string.ascii_letters

it's the same but you have a constant variable.

otherwise nice solution

ok i will try...:)

get_op(1,4,-3)= "subtract"

Nope, it should be 3. It's up to you to check both possibilities.

so what should we do

but in some case ,
get_op(1,4,-3)= "subtract"

get_op(4,1,3) = "subtract"

get_op(1, 4, 3) = 'subtract'

Also, get_op(4, 1, 3) = 'subtract'

That's because order of numbers (4 and 1) shouldn't matter, as mentioned in description.

sometimes target is num2 - num1
and sometimes target is num1-num2

They look ok, what's the problem?