From a Straight-arm hang position, tuck one leg and keep the other one fully extended.
Engage your scapulas ( Shoulder depression and Shoulder retraction ) and pull your body upward.
Go through the One-leg front lever position and keep going until the Inverted hang position, then reverse the motion.
The primary muscles work equally regardless of which leg you extend, so it is not necessary to count the exercise as unilateral: it is enough to alternate the legs with each set or repetition.