Use attributes inside the function to determine the length

Question

Write a VHDL function that will take two integer vectors, A and B, and find the dot product C = Σ a_i * b_i. The function call should be of the form DOT(A,B), where A and B are integer vector signals. Use attributes inside the function to determine the length and ranges of the vectors. Make no assumptions about the high and low values of the ranges. For example,

Output a warning if the ranges are not the same.