SyntaxFactory generate constructor with calling base class constructor

I wrote code which generates a new class in accordance with an initial state. Roslyn provides the class SyntaxFactory for it, but I don't understand how to generate a constructor by calling the base class, like this:

public TestClientApi(String entryPoint) : **base(entryPoint)**
{
    _entryPoint = entryPoint;
}

https://github.com/ddydeveloper/Roslyn.ApiClient.Codegen

Any idea?