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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 ChunksExist(self, chunk_numbers):
 """Do we have this chunk in the index?"""

    index_urns = {
        self.urn.Add(self.CHUNK_ID_TEMPLATE % chunk_number): chunk_number
        for chunk_number in chunk_numbers
    }

    res = {chunk_number: False for chunk_number in chunk_numbers}

    for metadata in aff4.FACTORY.Stat(index_urns):
      res[index_urns[metadata["urn"]]] = True

    return res