How can i use a bool variable to decide if to use a StartCoroutine ?

In one script at the top:

 public bool generationDelay = false;

Then in a method, there was only StartCoroutine i added all the IF statement using the bool variable:

 private void BeginGame()
     {
         mazeInstance = Instantiate(mazePrefab) as Maze;
 
         if (generationDelay == true)
         {
             StartCoroutine(mazeInstance.Generate(generationDelay));
         }
         else
         {
             mazeInstance.Generate(generationDelay);
         }
     }

Then in another script in the Generate method:

 public IEnumerator Generate (bool generationDelay) {
 
         if (generationDelay == true)
         WaitForSeconds delay = new WaitForSeconds(generationStepDelay);
         cells = new MazeCell[size.x, size.z];
         List<MazeCell> activeCells = new List<MazeCell>();
         DoFirstGenerationStep(activeCells);
         while (activeCells.Count > 0) {
             yield return delay;
             DoNextGenerationStep(activeCells);
         }
     }

When i added this line inside Generate:

  if (generationDelay == true)

I'm getting error on the line:

 WaitForSeconds delay = new WaitForSeconds(generationStepDelay);

The error message:

Embedded statement cannot be a declaration or labeled statement

And also error on the line: On the delay

 yield return delay;

The name 'delay' does not exist in the current context

What i want is a public bool variable to decide if to use or not StartCoroutine.