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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 get_digest_keys(self):
 """Returns a list of the type choices"""


        digest_keys = []
        for col in xrange(self.GetNumberCols()):
            digest_key = self.GetCellValue(self.has_header, col)
            if digest_key == "":
                digest_key = self.digest_types.keys()[0]
            digest_keys.append(digest_key)

        return digest_keys