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.
docstr: Register an implementation.
docstr_tok: ["Register","an","implementation","."]
code: def add_implementation(self, impl):
      """Register an implementation."""
      self._impls += [impl]
  
label_desc: Use image node_id 3 for calling the MultiImplRegister obj's underlying member method code with example usage: obj.add_implementation(impl) without return types