def GetSubmoduleName(fullname):
  """Determines the leaf submodule name of a full module name.

  Args:
    fullname: Fully qualified module name, e.g. 'foo.bar.baz'

  Returns:
    Submodule name, e.g. 'baz'. If the supplied module has no submodule (e.g.,
    'stuff'), the returned value will just be that module name ('stuff').
  """
  return fullname.rsplit('.', 1)[-1]