The lesbian, Countess Geschwitz, dances tango with Lulu, in ‘Pandora’s Box’ 1929

Ray Batchelor writes: What should we make of this 1929 queer tango from Weimar Germany? The clip shows Lulu dancing with Countess Augusta Geschwitz (Louise Brooks and Alice Roberts) and is probably the earliest film showing a lesbian dancing tango with another woman. Was it a tango they danced?