Did this inspire Erich Kaestner?

Famous German childrens books author Erich Kaestner wrote "Das doppelte Lottchen" (later filmed as "The Parent Trap" with Maureen O'Hara) in 1949. This movie "Twice Blessed" has the exact same plot, but it's from 1945. So I assume Kaestner must have caught this movie after WW II in a German movie theater and THEN wrote his famous book.
He is also the author of "Emil and the Detectives".

http://en.wikipedia.org/wiki/Erich_K%C3%A4stner