For string keys it can be as it is `dict(a=1, b=2, c=3)` vs `{"a": 1, "b": 2, "c": 3}`. There is a lot of `"` noise on the latter.
Without that, if Python allowed it, would it do given:
a = "xxx"
test_dict = {a=3, b=2}
would it take test_dict to mean {"xxx":3, "b":2} or {"a":3, "b":2} ?JS does the latter always, so the variable a is not related to the literal key a which is understood as an unquoted string "a":
> a = "xxx"
'xxx'
> test_dict = {a:3, b:2}
{ a: 3, b: 2 }
> test_dict["xxx"]
undefined
> test_dict["a"]
3dict(1=5, 6=7, 7="aaa")
dict(hashableInstance="foo", anotherHashableInstance=23, (1,5)=8)
except Python syntax choices of course.
And if they wanted a string, they'd do it like:
dict("1"=5, 6=7, 7="aaa")