Decorator to handle selecting the proper module for loaders.
    The decorated function is passed the module to use instead of the module
    name. The module passed in to the function is either from sys.modules if
    it already exists or is a new module. If the module is new, then __name__
    is set the first argument to the method, __loader__ is set to self, and
    __package__ is set accordingly (if self.is_package() is defined) will be set
    before it is passed to the decorated function (if self.is_package() does
    not work for the module it will be set post-load).
    If an exception is raised and the decorator created the module it is
    subsequently removed from sys.modules.
    The decorator assumes that the decorated function takes the module name as
    the second argument.

def module_for_loader(fxn):
    """Decorator to handle selecting the proper module for loaders.
    The decorated function is passed the module to use instead of the module
    name. The module passed in to the function is either from sys.modules if
    it already exists or is a new module. If the module is new, then __name__
    is set the first argument to the method, __loader__ is set to self, and
    __package__ is set accordingly (if self.is_package() is defined) will be set
    before it is passed to the decorated function (if self.is_package() does
    not work for the module it will be set post-load).
    If an exception is raised and the decorator created the module it is
    subsequently removed from sys.modules.
    The decorator assumes that the decorated function takes the module name as
    the second argument.
    """
    warnings.warn('The import system now takes care of this automatically.',
                  DeprecationWarning, stacklevel=2)
    @functools.wraps(fxn)
    def module_for_loader_wrapper(self, fullname, *args, **kwargs):
        with _module_to_load(fullname) as module:
            module.__loader__ = self
            try:
                is_package = self.is_package(fullname)
            except (ImportError, AttributeError):
                pass
            else:
                if is_package:
                    module.__package__ = fullname
                else:
                    module.__package__ = fullname.rpartition('.')[0]
            # If __package__ was not set above, __import__() will do it later.
            return fxn(self, module, *args, **kwargs)

    return module_for_loader_wrapper