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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 _normalize(self, metric_name, submit_method, prefix):
 """ Replace case-sensitive metric name characters, normalize the metric name, prefix and suffix according to its type. """

        metric_prefix = "mongodb." if not prefix else "mongodb.{0}.".format(prefix)
        metric_suffix = "ps" if submit_method == RATE else ""

        # Replace case-sensitive metric name characters
        for pattern, repl in iteritems(self.CASE_SENSITIVE_METRIC_NAME_SUFFIXES):
            metric_name = re.compile(pattern).sub(repl, metric_name)

        # Normalize, and wrap
        return u"{metric_prefix}{normalized_metric_name}{metric_suffix}".format(
            normalized_metric_name=self.normalize(metric_name.lower()),
            metric_prefix=metric_prefix,
            metric_suffix=metric_suffix,
        )