class_docstr: Utility class to inject multiple implementations of methods.
  
  An implementation must implement __call__ and is_supported with the same
  set of arguments. The registered implementations "is_supported" methods are
  called in reverse order under which they are registered. The first to return
  true is then invoked via __call__ and the result returned.
code: def __call__(self, *args, **kwargs):
      fails = []
      for impl in reversed(self._impls):
          if impl.is_supported(*args, **kwargs):
              return impl(*args, **kwargs)
          else:
              fails.append(type(impl).__name__)
      raise RuntimeError(
          "Missing implementation that supports: %s(*%r, **%r). Tried %r"
          % (self._name, args, kwargs, fails)
      )
  
label_desc: Use image node_id 4 for calling the MultiImplRegister obj's underlying member method code with example usage: obj.__call__() and returns: impl