❔ Can i not call a non static Method in a interface?

public interface IRegistry<B> {

    public virtual void Initialize() {
        
    }
    
    public T Register<T>(string name, Dictionary<string, object> registryList, T config) where T : B {
        registryList.Add(name, config);
        
        return config;
    }
}

public interface IRegistry<B> {

    public virtual void Initialize() {
        
    }
    
    public T Register<T>(string name, Dictionary<string, object> registryList, T config) where T : B {
        registryList.Add(name, config);
        
        return config;
    }
}