Return snmp value for the given OID.

def get(self,oid):
		"""Return snmp value for the given OID."""
		try:
			self.lock.acquire()
			if oid not in self.data:
				return "NONE"
			else:
				return self.base_oid + oid + '\n' + self.data[oid]['type'] + '\n' +	str(self.data[oid]['value'])
		finally:
			self.lock.release()