Here is an implementation of importlib.util.module_from_spec(). With this it makes PEP 451 conceptually work like:

  spec = importlib.util.find_spec(name)
  module = importlib.util.module_from_spec(spec)
  spec.loader.exec_module(module)

About the only other thing I can think of that people might still want is something like `importlib.util.load(spec)` so that they don't even need to care about whether load_module() or exec_module() is defined, but that can be a separate issue if it turns out people actually want something like that.