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  <xs:element id="bacq_ProceedsAllocatedToPublicRights" name="ProceedsAllocatedToPublicRights" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
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  <xs:element id="bacq_CashUnderwritingFeePayable" name="CashUnderwritingFeePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_UnderwritingAgreementMember" name="UnderwritingAgreementMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
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  <xs:element id="bacq_UnitsIssuedDuringPeriodSharesNewIssues" name="UnitsIssuedDuringPeriodSharesNewIssues" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_ClassAOrdinarySharesParValue00001PerShareMember" name="ClassAOrdinarySharesParValue00001PerShareMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_RightsEachRightEntitlingTheHolderToReceiveOnetenth110OfOneClassAOrdinaryShareMember" name="RightsEachRightEntitlingTheHolderToReceiveOnetenth110OfOneClassAOrdinaryShareMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_UnitsEachConsistingOfOneClassAOrdinaryShareAndOneRightMember" name="UnitsEachConsistingOfOneClassAOrdinaryShareAndOneRightMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_ScheduleOfCompanySAssetsAndLiabilitiesAbstract" name="ScheduleOfCompanySAssetsAndLiabilitiesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_CommitmentsandContingenciesDetailsTable" name="CommitmentsandContingenciesDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_DeferredFeePerUnit" name="DeferredFeePerUnit" type="dtr:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_OverAllotmentOptionPeriod" name="OverAllotmentOptionPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_UnderwriterCashDiscount" name="UnderwriterCashDiscount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xs:element id="bacq_AccruedOfferingCostsCurrent" name="AccruedOfferingCostsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_DeferredUnderwritingFeePayableNoncurrent" name="DeferredUnderwritingFeePayableNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_ShortTermPrepaidInsurance" name="ShortTermPrepaidInsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xs:element id="bacq_InterestEarnedOnMarketableSecuritiesHeldInTrustAccount" name="InterestEarnedOnMarketableSecuritiesHeldInTrustAccount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_FormationCostsPaidBySponsorInExchangeForIssuanceOfClassBOrdinaryShares" name="FormationCostsPaidBySponsorInExchangeForIssuanceOfClassBOrdinaryShares" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_PaymentOfOperationCostsThroughPromissoryNote" name="PaymentOfOperationCostsThroughPromissoryNote" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
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  <xs:element id="bacq_PrivatePlacementTextBlock" name="PrivatePlacementTextBlock" type="dtr:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_PreFundedInvestorPurchasedMember" name="PreFundedInvestorPurchasedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_PrinicipalAmount" name="PrinicipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xs:element id="bacq_PublicShareMember" name="PublicShareMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_SeriesACumulativeConvertiblePreferredStockMember" name="SeriesACumulativeConvertiblePreferredStockMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_SeriesAPreferredStockInvestmentMember" name="SeriesAPreferredStockInvestmentMember" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_TransactionCosts" name="TransactionCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xs:element id="bacq_MeasurementInputUnderlyingSharePriceMember" name="MeasurementInputUnderlyingSharePriceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_MeasurementInputPreadjustedValuePerShareRightMember" name="MeasurementInputPreadjustedValuePerShareRightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_MeasurementInputFairValuePerShareRightMember" name="MeasurementInputFairValuePerShareRightMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
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  <xs:element id="bacq_ScheduleOfBasicAndDilutedNetIncomePerOrdinaryShareAbstract" name="ScheduleOfBasicAndDilutedNetIncomePerOrdinaryShareAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
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  <xs:element id="bacq_PublicSharesRedemptionPercentage" name="PublicSharesRedemptionPercentage" type="dtr:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
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  <xs:element id="bacq_FounderShares1Member" name="FounderShares1Member" type="dtr:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_AggregateShareIssuedPercentage" name="AggregateShareIssuedPercentage" type="dtr:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_BusinessCombinationConsiderationsTransferredEquityInterestsIssuedAndIssuable" name="BusinessCombinationConsiderationsTransferredEquityInterestsIssuedAndIssuable" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xs:element id="bacq_NumberOfShareIssuedPerUnit" name="NumberOfShareIssuedPerUnit" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
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  <xs:element id="bacq_FairValueMeasuredOnValuationTechniques" name="FairValueMeasuredOnValuationTechniques" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xs:element id="bacq_SignificantAccountingPoliciesScheduleofBasicandDilutedNetIncomePerOrdinaryShareDetailsTable" name="SignificantAccountingPoliciesScheduleofBasicandDilutedNetIncomePerOrdinaryShareDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
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  <xs:element id="bacq_WorkingCapitalOutstandingLoans" name="WorkingCapitalOutstandingLoans" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_WorkingCapitalLoanAmount" name="WorkingCapitalLoanAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xs:element id="bacq_ThresholdPeriodAfterBusinessCombinationInWhichSpecifiedTradingDaysWithinAnySpecifiedTradingDayPeriodCommences" name="ThresholdPeriodAfterBusinessCombinationInWhichSpecifiedTradingDaysWithinAnySpecifiedTradingDayPeriodCommences" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_RestrictionsOnTransferPeriodOfTimeAfterBusinessCombinationCompletion" name="RestrictionsOnTransferPeriodOfTimeAfterBusinessCombinationCompletion" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_RelatedPartyTransactionsDetailsTable" name="RelatedPartyTransactionsDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xs:element id="bacq_PercentageOfIssuedAndOutstandingShares" name="PercentageOfIssuedAndOutstandingShares" type="dtr:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xs:element id="bacq_NumberOfTradingDays" name="NumberOfTradingDays" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_AdditionalSharesIssued" name="AdditionalSharesIssued" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xs:element id="bacq_FairValueMeasurementsScheduleofCompanysAssetsandLiabilitiesDetailsTable" name="FairValueMeasurementsScheduleofCompanysAssetsandLiabilitiesDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
</xs:schema>
