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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 output_file_name(self):
 """Name of the file where plugin's output should be written to."""


    safe_path = re.sub(r":|/", "_", self.source_urn.Path().lstrip("/"))
    return "results_%s%s" % (safe_path, self.output_file_extension)