class_docstr: A helper class with some side effects
  we can test.
class_docstr_tok: ["A","helper","class","with","some","side","effects","we","can","test","."]
code: def tick(self):
      self.count += 1
  
imports: from promise import Promise
  from .utils import assert_exception
  from threading import Event
label_desc: Use image node_id 2 for calling the Counter obj's underlying member method code with example usage: obj.tick() without return types