Initialize a AlignedElement object from a json dictionary.

def _from_dict(cls, _dict):
        """Initialize a AlignedElement object from a json dictionary."""
        args = {}
        if 'element_pair' in _dict:
            args['element_pair'] = [
                ElementPair._from_dict(x) for x in (_dict.get('element_pair'))
            ]
        if 'identical_text' in _dict:
            args['identical_text'] = _dict.get('identical_text')
        if 'provenance_ids' in _dict:
            args['provenance_ids'] = _dict.get('provenance_ids')
        if 'significant_elements' in _dict:
            args['significant_elements'] = _dict.get('significant_elements')
        return cls(**args)