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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 drop_index(self, name):
 """ Drops an index from this table. :param name: The index name :type name: str """

        name = self._normalize_identifier(name)
        if not self.has_index(name):
            raise IndexDoesNotExist(name, self._name)

        del self._indexes[name]