Testing for -3 10 9 -7 -3 9 10 -7 -8 -8 9 1 10 2 -3

It should work for random inputs too: [-3, 10, 9, -7, -8] should equal [-3, 9, 10, -7, -8]

But what's wrong with this output?
The first number that repeats is -3, then -10 then 9 and so on.

magnitude is a property, not a method. Nothing to fix.

there is error in python test
test.assert_approx_equals(Vector(examples[0]).magnitude, 3.741)
shoud be
test.assert_approx_equals(Vector(examples[0]).magnitude(), 3.741)
please fix it in all tests

The kata needs to be solved in-place, you are using O(N) space for keeping a copy of the a array

Thank you

Better to use lists extend()