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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _from_dict(cls, _dict):
 """Initialize a WordAlternativeResults object from a json dictionary."""

        args = {}
        if 'start_time' in _dict:
            args['start_time'] = _dict.get('start_time')
        else:
            raise ValueError(
                'Required property \'start_time\' not present in WordAlternativeResults JSON'
            )
        if 'end_time' in _dict:
            args['end_time'] = _dict.get('end_time')
        else:
            raise ValueError(
                'Required property \'end_time\' not present in WordAlternativeResults JSON'
            )
        if 'alternatives' in _dict:
            args['alternatives'] = [
                WordAlternativeResult._from_dict(x)
                for x in (_dict.get('alternatives'))
            ]
        else:
            raise ValueError(
                'Required property \'alternatives\' not present in WordAlternativeResults JSON'
            )
        return cls(**args)