class_docstr: Run length encoding of a mask.
  
  Don't instantiate this class directly, instead use the classmethods
  `from_coco` and `from_kaggle`.
code: def from_string(cls, s, sep=" "):
      return cls(lmap(int, s.split(sep)))
  
imports: from icevision.imports import *
  from icevision.utils import *
  from PIL import Image
label_desc: Use image node_id 5 for calling the RLE obj's underlying member method code with example usage: obj.from_string(cls, s, sep) and returns: cls