message: Verify checksum even for already existing files locally
diff: @@ -63,7 +63,7 @@ def fetch(url, filename, dirname = "remote_datasets", file_checksum = None):
  file_path = join(dirname, filename)
  - # Check that an existing file does not already exist at file_path
  + # Check for an already existing file at file_path
  if not exists(file_path):
  # Create directory if not existing
  if not exists(dirname):
  @@ -76,8 +76,7 @@ def fetch(url, filename, dirname = "remote_datasets", file_checksum = None):
  if file_checksum != checksum:
  raise IOError("{} has a SHA256 checksum : {}, "
  "different from expected : {}."
  - "The file may be corrupted or the given url may be wrong !".format(file_path, checksum,
  - file_checksum))
  + "The file may be corrupted or the given url may be wrong !".format(file_path, checksum, file_checksum))
  return file_path
  