Initialize a QueryEvidence object from a json dictionary.

def _from_dict(cls, _dict):
        """Initialize a QueryEvidence object from a json dictionary."""
        args = {}
        if 'document_id' in _dict:
            args['document_id'] = _dict.get('document_id')
        if 'field' in _dict:
            args['field'] = _dict.get('field')
        if 'start_offset' in _dict:
            args['start_offset'] = _dict.get('start_offset')
        if 'end_offset' in _dict:
            args['end_offset'] = _dict.get('end_offset')
        if 'entities' in _dict:
            args['entities'] = [
                QueryEvidenceEntity._from_dict(x)
                for x in (_dict.get('entities'))
            ]
        return cls(**args)