code: def _remote_file_size(url=None, file_name=None, pb_dir=None):
      
  
      # Option to construct the url
      if file_name and pb_dir:
          url = posixpath.join(config.db_index_url, pb_dir, file_name)
  
      response = requests.head(url, headers={'Accept-Encoding': 'identity'})
      # Raise HTTPError if invalid url
      response.raise_for_status()
  
      # Supposed size of the file
      remote_file_size = int(response.headers['content-length'])
  
      return remote_file_size
docs: Get the remote file size in bytes
  
      Parameters
      ----------
      url : str, optional
          The full url of the file. Use this option to explicitly
          state the full url.
      file_name : str, optional
          The base file name. Use this argument along with pb_dir if you
          want the full url to be constructed.
      pb_dir : str, optional
          The base file name. Use this argument along with file_name if
          you want the full url to be constructed.
  
      Returns
      -------
      remote_file_size : int
          Size of the file in bytes