Write the following function in OCAML

Problem 3. The Fibonacci k-step numbers are a generalization of the Fibonacci and Tetranacci sequences, where F_i = 0 for i 0, F₁ = 1, F₂ = 1, and for every j 3:

F_j = F_j1 + F_j2 + + F_jk,

i.e. F_j is the sum of the k previous numbers in the sequence. You will implement an OCaml function fib_k_step : int -> int -> int for computing these numbers efficiently.

(b) Implement an OCaml function fib_k_step : int -> int -> int, which accepts two integers n and k and, for a fixed k, computes in time linear in n the nth Fibonacci k-step number.2