code: def read_element_using_argtuple(self, argtuple):
  		
  
  		# doesn't support DELIMITED, only dict-based formats
  		if self.format == FMT_DELIMITED:
  			return None
  
  		node = self.cfg_dict
  		for key in argtuple:
  			node = node[key]
  		return node
docs: takes a tuple of keys
  		returns node found in cfg_dict
  		found by traversing cfg_dict by successive 
  		application of keys from element_path