Detect current input framework in project

Unity Engine
1

I’m writing an editor tool which is moving from Input Manager to the new Input System.
How can I determine which of these two frameworks is active in the current project ?
That would allow me to display a warning to my users.

TIA, Patrick

2

Found it :

When the new input backends are enabled, the ENABLE_INPUT_SYSTEM=1 C# #define is added to builds. Similarly, when the old input backends are enabled, the ENABLE_LEGACY_INPUT_MANAGER=1 C# #define is added. Because both can be enabled at the same time, it is possible for both defines to be 1 at the same time.

From Input System installation guide