code: def _get_child_from_path(self, path):
          
  
          keys = path.split(".")
  
          this_child = self
  
          for key in keys:
  
              try:
  
                  this_child = this_child._get_child(key)
  
              except KeyError:
  
                  raise KeyError("Child %s not found" % path)
  
          return this_child
docs: Return a children below this level, starting from a path of the kind "this_level.something.something.name"
  
          :param path: the key
          :return: the child