code: def descendants(self,collapseLists=True):
  		
  
  		if not collapseLists:
  			return self.children
  
  		if not self.children:
  			return []
  
  		if type(self.children[0])==type([]):
  			return [x[0] for x in self.children]
  
  		return self.children
docs: A more genteel method of accessing an object's children (than self.children)
  		If collapseLists==True, the returned list is guaranteed not to be a list of lists.
  		If collapseLists==False, the returned list *may* be a list of lists, [cf. self.children]
  			in the case of optionality among children
  			eg, a line's children is a list of lists of Words.