code: def scoped(cls, optionable, removal_version=None, removal_hint=None):
      
      return SubsystemDependency(cls, optionable.options_scope, removal_version, removal_hint)
docs: Returns a dependency on this subsystem, scoped to `optionable`.
  
      :param removal_version: An optional deprecation version for this scoped Subsystem dependency.
      :param removal_hint: An optional hint to accompany a deprecation removal_version.
  
      Return value is suitable for use in SubsystemClientMixin.subsystem_dependencies().