Dear All,

I run the sample code to solve a differential equation from tutorial.

```
const p0 = 0.2; const q0 = 0.3; const v0 = 1; const d0 = 5
const p1 = 0.2; const q1 = 0.3; const v1 = 1; const d1 = 1
const d2 = 1; const beta0 = 1; const beta1 = 1; const tau = 1
function bc_model(du,u,h,p,t)
du[1] = (v0/(1+beta0*(h(p, t-tau)[3]^2))) * (p0 - q0)*u[1] - d0*u[1]
du[2] = (v0/(1+beta0*(h(p, t-tau)[3]^2))) * (1 - p0 + q0)*u[1] +
(v1/(1+beta1*(h(p, t-tau)[3]^2))) * (p1 - q1)*u[2] - d1*u[2]
du[3] = (v1/(1+beta1*(h(p, t-tau)[3]^2))) * (1 - p1 + q1)*u[2] - d2*u[3]
end
lags = [tau]
h(p, t) = ones(3)
tspan = (0.0,10.0)
u0 = [1.0,1.0,1.0]
prob = DDEProblem(bc_model,u0,h,tspan; constant_lags=lags)
alg = MethodOfSteps(Tsit5())
sol = solve(prob,alg)
```

however, I directly get an error saying:

MethodError: no method matching OrdinaryDiffEq.DEOptions

I cannot google it find a method to solve this issue. Can anyone give any suggestion?

Thank you very much!

Peter