code: def move(self, newX1) :
  		
  		if self.x1 != None and self.x2 != None :
  			offset = newX1-self.x1
  			aux_moveTree(offset, self)
  		elif len(self.children) > 0 :
  			offset = newX1-self.children[0].x1
  			aux_moveTree(offset, self)
docs: Moves tree to a new starting position, updates x1s of children