gistfile1.py

class Boiler:
    def safety_check(self):
        # Convert fixed-point floating point
        temperature = self.modbus.read_holding()
        pressure_psi = self.abb_f100.register / F100_FACTOR
        if (psi_to_pascal(pressure_psi) > MAX_PRESSURE or
                temperature > MAX_TEMPERATURE):
            # Shutdown!
            self.pnoz.relay[15] &= MASK_POWER_COIL
            self.pnoz.port.write('$PL,15\0')
            sleep(RELAY_RESPONSE_DELAY)
            # Successful shutdown?
            if self.pnoz.relay[16] & MASK_POWER_OFF:
                # Play alarm
                with open(BUZZER_MP3_FILE) as f:
                    play_sound(f.read())

Line 13 wouldn't work very well. Replace "& a m p ;" with just "&".

Came to say the same thing.