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Hi, I'm working on an S4 class that is expected to behave like an array. I have some difficulties when defining '[' and I wonder if someone could point me to the right direction: 1) Call the S4 object "obj" 2) Assume dim(obj) = c(10, 4, 2) 3) Suppose someone calls: obj[1:3,] , which is a mistake, given dim(obj); how do I detect such situations? Thank you very much for