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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 new_reviewer(self, name, anomalous=None):
 """Create a new reviewer. Args: name: name of the new reviewer. anomalous: initial anomalous score. (default: None) Returns: A new reviewer instance. """

        n = self._reviewer_cls(
            self, name=name, credibility=self.credibility, anomalous=anomalous)
        self.graph.add_node(n)
        self.reviewers.append(n)
        return n