code: def extract_firmware(self):
          '''
          Extract camera firmware (tag is called 'software' in EXIF)
          '''
          fields = ['Image Software']
          software, _ = self._extract_alternative_fields(
              fields, default="", field_type=str)
          return softwarf extract_firmware(self):
          '''
          Extract camera firmware (tag is called 'software' in EXIF)
          '''
          fields = ['Image Software']
          software, _ = self._extract_alternative_fields(
              fields, default="", field_type=str)
          return software
docs: Extract camera firmware (tag is called 'software' in EXIF)