Photo: Brigitte Lacombe for New York Magazine In December, the film director Mira Nair was in India preparing for her upcoming feature, Amri, about the life of the Indo-Hungarian painter Amrita Sher-Gil, whom she called “our Frida Kahlo.” She said these whirlwind weeks, which involved her jetting from Amritsar, next to the Pakistan border, to Kochi, near the subcontinent’s southern tip, were “deeply painstaking but thrilling because this particular film has taken me four years to cook and now