Why the lioness nursed a leopard cub ?

Nature will always amaze....and the story of a lioness in Gir Forest India adopting a leopard cub is one of the more astounding ones. As supreme predators and competitors in the wild these two species usually don't tolerate each other. Lions generally kill leopards any chance they get. It's intriguing to speculate on the outcome of this unusual arrangement that foresters have no idea about how it occurred. Observations of the family group of lion cubs with the leopard cub nursing show a lioness caring for the leopard cub as if it was one of her own. What happens when they join the pride will be even more to wonder about, will the cub be accepted or singled out and killed as you would expect ? It is a leopard with a whole other way of living as a solitary cat rather than part of a pride like the lions so it really is fascinating to think about. I hope the little guy gets accepted but the chances are probably slim.
In 2017 a lioness was spotted nursing a leopard cub in Tanzania but no one knew how that had happened or what the outcome was. What is understood is that the lioness accepts the foreign cub because she is nursing cubs or has perhaps lost her own just as a domestic cat will adopt kittens that are not her theirs.