text: function repeat(n,action){
  //for (let i in n)
  for(let i=0;i<n;i++)
      action(i);
  };
  
  repeat(5,console.log);
  
  let labels = [];
  repeat(5, i => { labels.push(`Unit ${i + 1}`);
  });
  console.log("arrow try:",labels);
  
  repeat(5, (j)=> { 
      labels.push(`Unit ${j + 1}`);
      console.log("hello");
  }
  );
  console.log("arrow try2:",labels);