message: Fix sample usage of learn.utils.gc: re.escape() the base_dir before matching.
diff: @@ -32,13 +32,14 @@ Note that functions should always return a sorted list.
  For example,
  base_dir = "/tmp"
  - # create the directories
  + # Create the directories.
  for e in xrange(10):
  os.mkdir("%s/%d" % (base_dir, e), 0o755)
  - # create a simple parser that pulls the export_version from the directory
  + # Create a simple parser that pulls the export_version from the directory.
  + path_regex = "^" + re.escape(base_dir) + "/(\\d+)$"
  def parser(path):
  - match = re.match("^" + base_dir + "/(\\d+)$", path.path)
  + match = re.match(path_regex, path.path)
  if not match:
  return None
  return path._replace(export_version=int(match.group(1)))
  @@ -54,7 +55,7 @@ For example,
  both = gc.union(every_fifth, largest_three)
  print(both(all_paths)) # shows ["/tmp/0", "/tmp/5",
  # "/tmp/7", "/tmp/8", "/tmp/9"]
  - # delete everything not in 'both'
  + # Delete everything not in 'both'.
  to_delete = gc.negation(both)
  for p in to_delete(all_paths):
  gfile.DeleteRecursively(p.path) # deletes: "/tmp/1", "/tmp/2",
  