code: def _convert(cls, record):
          
          if not record:
              return {}
  
          converted_dict = {}
          for field in cls.conversion:
              key = field[0]
              if len(field) >= 2 and field[1]:
                  converted_key = field[1]
              else:
                  converted_key = key
              if len(field) >= 3 and field[2]:
                  conversion_method = field[2]
              else:
                  conversion_method = cls.default_conversion_method
              if len(field) >= 4:
                  converter = field[3]
              else:
                  converter = None
              try:
                  value = conversion_method(record[key])
              except KeyError:
                  continue
              if converter:
                  value = converter._convert_internal(value)
              if converted_key is APPEND:
                  if isinstance(value, list):
                      for v in value:
                          converted_dict.update(v)
                  else:
                      converted_dict.update(value)
              else:
                  converted_dict[converted_key] = value
          return converted_dict
docs: Core method of the converter. Converts a single dictionary into another dictionary.