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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 validate_gaslimit(self, header: BlockHeader) -> None: """ Validate the gas limit on the given header. """

        parent_header = self.get_block_header_by_hash(header.parent_hash)
        low_bound, high_bound = compute_gas_limit_bounds(parent_header)
        if header.gas_limit < low_bound:
            raise ValidationError(
                "The gas limit on block {0} is too low: {1}. It must be at least {2}".format(
                    encode_hex(header.hash), header.gas_limit, low_bound))
        elif header.gas_limit > high_bound:
            raise ValidationError(
                "The gas limit on block {0} is too high: {1}. It must be at most {2}".format(
                    encode_hex(header.hash), header.gas_limit, high_bound))