ML-Agents and inheritance. An issue.

Hi people, I need help with building an efficient method to make car control work in a racing game, both for the player and for the AI.

Before wanting to implement ML-Agents, I have been using a class that stores the variables for each command, together with two subclasses that differentiate the player's inputs from those of the AI, through inheritance.

 public class MasterInput : MonoBehaviour
 {
     protected float accel;
     protected float brake;
     protected float steer;
     protected bool boost;
 
     //stuff
 }
 
 public class PlayerInput : MasterInput
 {
     //functional stuff with New Input System
 }
 
 public class MachineInput : MasterInput
 {
     //functional stuff with AI-related script
 }

Which are used to control the vehicle, regardless of who is controlling it. It even executes specific commands depending on the script loaded in the GameObject.

 public class CarMovement : MonoBehaviour
 {
     //car variables
 
     MasterInput mInput;
 
     void Start()
     {
         mInput = GetComponent<MasterInput>();
         
         if (mInput is PlayerInput)
         {
             // do specific thing
         }
         else if (mInput is MachineInput)
         {
             // do specific thing
         }
     }
 
     //stuff
 }

However, when I have wanted to integrate with ML-Agents, I get the error CS1721.

 public class MachineInput : Agent, MasterInput
 {
     //stuff failed to work
 }

I would like to know how this can be solved, if possible.