code: function deleteFile(filePath) {
    return new Promise((resolve, reject) => {
      fs.unlink(filePath, (err) => {
        if (err) {
          reject(err);
          return;
        }
        resolve(filePath);
      });
    });
  }
docs: Delete a file from the file system
  @param {string} filePath path and filename: the file to delete
  @returns {Promise<string>} resolve with the filePath deleted