class_docstr: Combine several waiting strategies.
code: def __call__(self, retry_state):
      return sum(x(retry_state=retry_state) for x in self.wait_funcs)
  
imports: import abc
  import random
  import six
  from tenacity import _utils
label_desc: Use image node_id 2 for calling the wait_combine obj's underlying member method code with example usage: obj.__call__(retry_state) and returns: sum