code: def _resolve_file_name(source, destination):
          
          number = 1
          if os.path.exists(os.path.join(destination, os.path.basename(source) + '.zip')):
              while True:
                  zip_filename = os.path.join(destination, os.path.basename(source) + '_' + str(number) + '.zip')
                  if not os.path.exists(zip_filename):
                      break
                  number = number + 1
          else:
              zip_filename = os.path.join(destination, os.path.basename(source) + '.zip')
          return zip_filename
docs: Create a filename for the destination zip file.