The function addNewTeachers() works without any parameters. So, why should I create any parameters in this function?

let newTeachers = [
    {
        name: 'James',
        topicArea: 'Javascript'
    },
    {
        name: 'Treasure',
        topicArea: 'Javascript'
    }
];


const teachers = [
    {
        name: 'Ashley',
        topicArea: 'Javascript'
    }
];


const courses = ['Introducing JavaScript',
                'JavaScript Basics',
                'JavaScript Loops, Arrays and Objects',
                'Getting Started with ES2015',
                'JavaScript and the DOM',
                'DOM Scripting By Example'];


const i = courses.length;



function addNewTeachers() {

  for ( let i = 0; i < newTeachers.length; i++ )
    teachers.push ( newTeachers[i] );
}


function printTreehouseSummary() {
    // TODO: fix this function so that it prints the correct number of courses and   teachers 

  for (let i = 0; i < teachers.length; i++) {
     console.log(`${teachers[i].name} teaches ${teachers[i].topicArea}`);
    }

  console.log(`Treehouse has ${i} JavaScript courses, and ${teachers.length} Javascript teachers`);
}


addNewTeachers();
printTreehouseSummary();