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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 _map_input(self, input_stream):
 """ Iterate over input and call the mapper for each item. If the job has a parser defined, the return values from the parser will be passed as arguments to the mapper. If the input is coded output from a previous run, the arguments will be splitted in key and value. """

        for record in self.reader(input_stream):
            for output in self.mapper(*record):
                yield output
        if self.final_mapper != NotImplemented:
            for output in self.final_mapper():
                yield output
        self._flush_batch_incr_counter()