def __call__(self, element):
        """
        Reads a row from your annotations dict and
        transfer it to a single value

        Args:
            element: elem in your dataset

        Returns:
            dtype: Scalar value
        """
        scalar = self.dtype(element.get(self.input_key, self.default_value))
        if self.one_hot_classes is not None:
            scalar = get_one_hot(scalar, self.one_hot_classes, smoothing=self.smoothing)
        output = {self.output_key: scalar}
        return output

        Reads a row from your annotations dict and
        transfer it to a single value

        Args:
            element: elem in your dataset

        Returns:
            dtype: Scalar value
        
catalyst/contrib/data/reader.py