docs: def walk_level(path, level=1):
      """Like os.walk, but takes `level` kwarg that indicates how deep the recursion will go.
  
      Notes:
          TODO: refactor `level`->`depth`
  
      References:
          http://stackoverflow.com/a/234329/623735
  
      Args:
          path (str):  Root path to begin file tree traversal (walk)
              level (int, optional): Depth of file tree to halt recursion at.
              None = full recursion to as deep as it goes
              0 = nonrecursive, just provide a list of files at the root level of the tree
              1 = one level of depth deeper in the tree
  
      Examples:
          >>> root = os.path.dirname(__file__)
          >>> all((os.path.join(base,d).count('/') == (root.count('/')+1))
          ...     for (base, dirs, files) in walk_level(root, level=0) for d in dirs)
          True
      """
      if level is None:
          level = float('inf')
      path = expand_path(path)
      if os.path.isdir(path):
          root_level = path.count(os.path.sep)
          for root, dirs, files in os.walk(path):
              yield root, dirs, files
              if root.count(os.path.sep) >= root_level + level:
                  del dirs[:]
      elif os.path.isfile(path):
          yield os.path.dirname(path), [], [os.path.basename(path)]
      else:
          raise RuntimeError("Can't find a valid folder or file for path {0}".format(repr(path)))