Kot.Signaturesmodule type BUFFER = sig ... endmodule type BUFFER8 = sig ... endThe signature BUFFER8 extends the signature BUFFER with extra operations. All of these operations are in principle redundant: that is, they can be implemented in terms of the basic operations offered by BUFFER. Nevertheless, it is useful to identify these operations, for two reasons: first, their use makes client code more readable; second, a direct implementation of these operations is more efficient than an indirect implementation in terms of the basic operations.