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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 check_children(self):
        '''
        Check the children once
        '''
        if self._restart_processes is True:
            for pid, mapping in six.iteritems(self._process_map):
                if not mapping['Process'].is_alive():
                    log.trace('Process restart of %s', pid)
                    self.restart_process(pid)