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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 eth_getBlockHeaderByNumber(self, number):
 """Get block header by block number. :param number: :return: """

        block_hash = self.reader._get_block_hash(number)
        block_number = _format_block_number(number)
        return self.reader._get_block_header(block_hash, block_number)