class Timer( object ):
	def __init__( self, start, end, step, continuous = True ):
		self._initial = start	
		self._start = start
		self._end = end
		self._step = step
		self._continuous = continuous

	def update( self ):
		self._start += self._step
		if self._start >= self._end:
			if self._continuous:
				self._start = self._initial
			return True
		else:
			return False
