def increment(self, key):
		if key == 'build':
			self.build += 1
		elif key == 'revision':
			self.revision += 1
			self.build = 0
		elif key == 'minor':
			self.minor += 1
			self.revision = 0
			self.build = 0
		elif key == 'major':
			self.major += 1
			self.minor = 0
			self.revision = 0
			self.build = 0