Prove that the following program is correct with respect to its given specification. # Pre: w is a nonempty sequence of positive integers; It is a positive integer. # Post: Return True if w has a subsequence v such that sum(v)=t; Return False otherwise. SubseqSum(w, t): == t: 1. if w[0] return True 2. if len(w) == 1: return False 3. y = w[1:] #y is w with its first element removed 4. if SubseqSum(y, t): return True 5. if w[0] > t: return False 6. else: return SubseqSum(y, t - w[0])