<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def open(self, bus):
 """ Open a given i2c bus. :param bus: i2c bus number (e.g. 0 or 1) :type bus: int """

        self.fd = os.open("/dev/i2c-{}".format(bus), os.O_RDWR)
        self.funcs = self._get_funcs()