P filed a petition for expropriation asserting a taking of the land, buildings, and equipment of D, a Florida corporation. D removed the case to the District Court on the basis of diversity of citizenship. The district judge, on his own motion, ordered that 'Further proceedings herein, therefore, will be stayed until the Supreme Court of Louisiana has been afforded an opportunity to interpret Act 111 of 1900,' the authority on which the city's expropriation order was based. The Court of Appeals reversed, holding that the procedure adopted by the district judge was not available in an expropriation proceeding. The Supreme Court granted certiorari.