<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def run_step(self):
 """Write in to out, replacing strings per the replace_pairs."""

        formatted_replacements = self.context.get_formatted_iterable(
            self.replace_pairs)

        iter = StreamReplacePairsRewriterStep.iter_replace_strings(
            formatted_replacements)
        rewriter = StreamRewriter(iter)
        super().run_step(rewriter)