system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
"""
hereof constitutes a sole and integral agreement regarding the purpose of the same and replaces any previous agreement that has not been written in this Contract. 26.2 The following documents are an integral part of the Contract: 26.3 Likewise, all regulations and procedures that ECOPETROL has established for the development of the activities being the purpose hereto are an integral part of this Contract. CLAUSE TWENTY-SEVENTH LEGAL REGIME 27.1 The relation established in the Contract hereof is of commercial nature and therefore is governed by the regulations of Colombian private law. CLAUSE TWENTY-EIGHTH NOTIFICATIONS 28.1 All communications and invoices between the SENDER and ECOPETROL delivered as a result of this Contract shall require for its validity to be in writing, and depending on the will of the Party issuing it, they will have to be: 28.2 All communications shall deemed as served and valid: ANNEX 1 MANUAL OF THE SHIPPER OF THE ECOPETROL S A PIPELINE ANNEX 2 GUIDELINES FOR THE ADMINISTRATION OF RECEIVABLE SERVICES OF ECOPETROL ANNEX 3 GENERAL CLAUSES OF ECOPETROL FOR PERFORMANCE POLICIES ANNEX 4 STAND-BY LETTER OF CREDIT FORM a) delivered personally; or b) transmitted by facsimile, electronic mail or any other means through which it may be proved its delivery and reception (with proved reception and confirmation by mail). a) On the reception date if delivered personally, or b) Twenty four (24) hours after the transmission date, if transmitted by facsimile, electronic mail or any other means through which its delivery and reception may be proved; provided however, confirmation is received within the following three (3) days; whatever occurs first. 15 28.3 Each Party may change the address for these purposes, with previous written communication to the other Party with fifteen (15) calendar days in before the expected date for such change. 28.4 All notifications and communications to be made to the Parties as a result of the execution of this Contract shall be delivered to the addresses indicated in the Specific Conditions. CLAUSE TWENTY-NINTH MISCELLANEOUS 29.1 Severability: the voidance, nullity or inefficacy of any provision of this Contract shall not affect the validity, efficacy and enforceability of all other provisions of the same. In these events the Parties are obliged to negotiate in good faith a clause resulting legally valid, and enforceable, whose purpose is the same of the provision or provisions having vices of nullity, invalidity or non-enforceability, as the case may be. 29.2 Administration and Inspection: ECOPETROL shall designate an administrator and inspector of the Contract, whose functions shall be established in the Manual of Administration and Inspection of ECOPETROL. 29.3 Survival: The termination of this Contract shall not relieve the Parties from any obligation towards the other Party pursuant to this Contract, or any other loss, cost, damage, expense or responsibility which may occur under this Contract before or as a result of said termination. CLAUSE THIRTEENTH PERFECTION AND EXECUTION 30.1 The Contract hereof is perfected with the subscription of the same. For its execution the approval of the bond assumed by the SENDER is required. 16 ANNEX 1 MANUAL FOR THE TRANSPORTER OF PIPELINES ECOPETROL S A Operation and Transport Regulations Version 1 MANUAL FOR THE TRANSPORTER OF PIPELINES ECOPETROL S A TABLE OF CONTENTS CLAUSE 1. PURPOSE 3 CLAUSE 2 DEFINITIONS 3 CLAUSE 3 GENERAL DESCRIPTION OF THE PIPELINE 10 CLAUSE 4 OBLIGATIONS OF THE PARTIES 10 CLAUSE 5 FEES 13 CLAUSE 6 SPECIAL SERVICES 14 CLAUSE 7 ADJUSTMENT OF THE EFFECTIVE CAPACITY OF THE SYSTEM DUE TO VARIATIONS IN THE SPECIFICATIONS OF HYDROCARBONS 14 CLAUSE 8 PROJECTIONS, NOMINATION AND TRANSPORTATION SCHEDULE OF THE PIPELINE 15 CLAUSE 9 BALANCE IN EXCESS OR DEFECT 18 CLAUSE 10 PRIORITIES IN THE NOMINATION PROCESS 19 CLAUSE 11 REJECTION OF A TRANSPORTATION REQUEST 20 CLAUSE 12 QUALITY REQUIREMENTS 21 CLAUSE 13 DETERMINATION OF QUANTITIES AND QUALITY 22 CLAUSE 14 VOLUMETRIC COMPENSATION FOR QUALITY 25 CLAUSE 15 BULLETIN OF TRANSORTATION BY THE PIPELINE - BTO 26 CLAUSE 16 SPECIAL TRANSPORTATION CONDITIONS 28 CLAUSE 17 REGULATIONS FOR THE TRANSPORTATION OF SEGREGATED HYDROCARBON 29 CLAUSE 18 RISKS AND RESPONSIBILITY 29 CLAUSE 19 FILLING THE PIPELINE OR FILLING THE LINE 31 CLAUSE 20 HANDLING LOSSES IN THE PIPELINE 31 CLAUSE 21 CLAIMS 33 1 Operation and Transport Regulations Version 1 CLAUSE 22 SANCTIONS TO OPERATING AGENTS FOR NON-PERFORMANCE OF THE TRANSPORTATION SCHEDULE 33 CLAUSE 23 HYDROCARBON AFFECTED BY LITIGATION 34 CLAUSE 24 INVESTMENTS IN THE PIPELINE 35 CLAUSE 25 SOLE RISK PROPOSALS 36 CLAUSE 26 PROCEDURES FOR COORDINATION OF OPERATIONS, COMMUNICATIONS AND EMERGENCY ASSISTANCE 38 CLAUSE 27
"""

Extract the exact clause related to "Anti-Assignment" from the excerpt above.