Register new user on WordPress with role

user_registration_wp.php

/*
* Place this code on function.php or other included file on function.php
*/
//new user email
$email_address = 'hemraj7171@gmail.com';
//new manual password or generate password
//$password = wp_generate_password( 12, false );
$password = 'adminpassword';
//username
$username = 'hemraj7171';
//user role
$user_role = 'administrator';
//check username and email
if( null == username_exists( $username ) && !email_exists( $email_address ) ) {
  //create new user
  $user_id = wp_create_user( $username, $password, $email_address );
  // Set the nickname
  wp_update_user(
    array(
      'ID'          =>    $user_id,
      'nickname'    =>    $username
    )
  );

  // Set the role
  $user = new WP_User( $user_id );
  $user->set_role( $user_role );

}