message: Check if the wanted file already exists locally before downloading
diff: @@ -60,11 +60,15 @@ def fetch(url, filename, dirname = "remote_datasets", file_checksum = None):
  file_path: string
  Full path of the created file.
  """
  - if not exists(dirname):
  - makedirs(dirname)
  file_path = join(dirname, filename)
  + # Check that an existing file does not already exist at file_path
  + if not exists(file_path):
  + # Create directory if not existing
  + if not exists(dirname):
  + makedirs(dirname)
  +
  urlretrieve(url, file_path)
  if file_checksum is not None:
  