Help with deSolveDiffEq

New to Julia
3

In function integr_ODE! (du, u, t), I do not declare parameters. Should I in the declaration of the function, enter it, even though in the body of the function I don’t use them?

function integrate_ODE!(du,u,t)
    du[1] = -0.4*u[1] - u[2]
    du[2] = u[1] + 0.45*u[2]   
end