Initialize a Conversions object from a json dictionary.

def _from_dict(cls, _dict):
        """Initialize a Conversions object from a json dictionary."""
        args = {}
        if 'pdf' in _dict:
            args['pdf'] = PdfSettings._from_dict(_dict.get('pdf'))
        if 'word' in _dict:
            args['word'] = WordSettings._from_dict(_dict.get('word'))
        if 'html' in _dict:
            args['html'] = HtmlSettings._from_dict(_dict.get('html'))
        if 'segment' in _dict:
            args['segment'] = SegmentSettings._from_dict(_dict.get('segment'))
        if 'json_normalizations' in _dict:
            args['json_normalizations'] = [
                NormalizationOperation._from_dict(x)
                for x in (_dict.get('json_normalizations'))
            ]
        return cls(**args)