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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 Source object from a json dictionary."""

        args = {}
        if 'type' in _dict:
            args['type'] = _dict.get('type')
        if 'credential_id' in _dict:
            args['credential_id'] = _dict.get('credential_id')
        if 'schedule' in _dict:
            args['schedule'] = SourceSchedule._from_dict(_dict.get('schedule'))
        if 'options' in _dict:
            args['options'] = SourceOptions._from_dict(_dict.get('options'))
        return cls(**args)