integrator-using functions should return NaN on non-successful integrator steps

Hello again!

Now I try to calculate the Lyapunov spectrum in a two-parameter plane. But a warning comes when I choose some of the parameter regions:

Warning: Instability detected. Aborting

From what I googled, the warning comes because it returns a NAN in the trajectory. I am thinking if I can use the 'isnan' function to skip those parameter sets that cause the NAN and continue my loop. Since the lyapunovspectrum function is built-in, I am looking for your help.

Here is my code:

using DynamicalSystems, CairoMakie, GLMakie
using OrdinaryDiffEq
using DelimitedFiles
using ProgressMeter
function chaotictest(u, p, t)
    k1, k2 = p
    x, y, z = u
    dx = y
    dy = z
    dz = k1-7*y+x^2+k2*z
    return SVector(dx, dy, dz)
end
u0 = [0.01, 0.01, 0.01]
para = [-1.0, -1.0] 
ds = ContinuousDynamicalSystem(chaotictest, u0, para)
diffeq = (alg = Tsit5(), adaptive = false, dt = 0.001)
as = -1:0.1:8;  
bs = -1.0:0.05:0.01;
nloop = length(as)*length(bs)
cordiλ = zeros(nloop, 2+3)
λs = zeros(nloop, 3)
paras = zeros(nloop, 2)
cirnum = 0
prog = Progress(nloop; showspeed=true)
for (i, a) in enumerate(as)
    for (j, b) in enumerate(bs)
         global cirnum = cirnum + 1
    set_parameter!(ds, 1, a)
    set_parameter!(ds, 2, b)  
    λs[cirnum, :] .= lyapunovspectrum(ds, 2000; Ttr=3000, diffeq)
    paras[cirnum, :] .= [a, b]
    global cordiλ = [paras λs]
    next!(prog)
end
end