<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def move(self, newX1) : 		"""Moves tree to a new starting position, updates x1s of children"""

		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)