code: def battery_charge_current(self):
          
          msb = self.bus.read_byte_data(AXP209_ADDRESS, BATTERY_CHARGE_CURRENT_MSB_REG)
          lsb = self.bus.read_byte_data(AXP209_ADDRESS, BATTERY_CHARGE_CURRENT_LSB_REG)
          # (12 bits)
          charge_bin = msb << 4 | lsb & 0x0f
          # 0 mV -> 000h,	0.5 mA/bit	FFFh -> 1800 mA
          return charge_bin * 0.5
docs: Returns current in mA