# Return the class `self` in the class hierarchy of the module `mmodule`.
	#
	# SEE: `MModule::flatten_mclass_hierarchy`
	# REQUIRE: `mmodule.has_mclass(self)`
	fun in_hierarchy(mmodule: MModule): POSetElement[MClass]
	do
		return mmodule.flatten_mclass_hierarchy[self]
	end