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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 download_urls(self):
 """Returns download urls for this config."""

    urls = {
        tfds.Split.TRAIN: ["train_clean100"],
        tfds.Split.VALIDATION: ["dev_clean"],
        tfds.Split.TEST: ["test_clean"],
    }
    if self.data in ["all", "clean360"]:
      urls[tfds.Split.TRAIN].append("train_clean360")
    if self.data == "all":
      urls[tfds.Split.TRAIN].extend(["train_clean360", "train_other500"])
      urls[tfds.Split.VALIDATION].append("dev_other")
      urls[tfds.Split.TEST].append("test_other")

    urls = {
        split: [_DL_URLS[name] for name in names
               ] for split, names in urls.items()
    }
    return urls