SageMATH failed to solve ODE with Symbolic Integration

Question

I'm trying to solve an exact integration of a nonlinear ODE using SageMath.

I'm trying to find time function $x = x(t)$ integrating ODE $\dot{x} = b(2+\sqrt(1-x^2))(1-x^2)$ with SAGEMATH code below:

t = var('t')
x=function('x')(t)
var('b', domain='positive')
ode = diff(x,t)==b*(2+sqrt(1-x^2))*(1-x^2)
sol = desolve(ode, x,ivar=t); sol

b is a constant at equation.

But SAGEMATH returns notifications like "RuntimeError: ECL says: Error executing code in Maxima: changevar: fourth argument must be an atom; found: 'x(_SAGE_VAR_t)" and "ECL says: Error executing code in Maxima: changevar: fourth argument must be an atom; found: 'x(_SAGE_VAR_t)".

Does anyone have an idea how to resolve this?

Thanks.