Any study in linguistics will argue that there is no such thing as improper english. In that light of this, I present to you the following True Chicago double negatives:
I'm not gunna do dat no, not now, not ever.
Ain't nobody gunna tell me not to do dat.
I don't want nothin to do wit you.
... And the most famous double negative in Chicago history.... "Chicago ain't no sissy town" by "Hinky Dink" Kenna, the 1st Ward alderman ( 1897-1923) and "Lord of the Levee district".