Write a function matrix_add(a, b) that produces the result of adding two objects of type matrix, with kind parameter default real, as defined in this section. If a and b are not conformable, the...

Write a function matrix_add(a, b) that produces the result of adding two objects

of type matrix, with kind parameter default real, as defined in this section. If a

and b are not conformable, the result should be a 0 u0 matrix. Test the function.