As 7 Chaves de Baldpate

In the second sound version of George M. Cohan's play based on the Earl Derr Biggers novel, Gene Raymond is the novelist come to a closed hotel. He has bet a friend he can write a novel in 24 hours, and has been offered the site, free from distraction, because he has the only key. As the title tells you, there are six others, and a variety of beautiful, wacky and threatening characters keep him amusedly distracted from his typewriter.

There are, fittingly, a total of seven big-screen version of this story, although a couple seem missing in action. I don't think this is the earliest source novel in the Old Dark House genre. I believe it arose as a burlesque of the Gothic Romance. However, it seems to have seniority in the movies. The supporting cast, includes Moroni Olsen, Margaret Callahan, Erin O'Brien-Moore, Eric Blore, Grant Mitchell, Walter Brennan, and Henry Travers as a woman-hating hermit and part-time ghost.