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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 get_projected_fields(self, req):
 """ Returns the projected fields from request. """

        try:
            args = getattr(req, 'args', {})
            return ','.join(json.loads(args.get('projections')))
        except (AttributeError, TypeError):
            return None