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:
"""
except either Party may assign this Agreement without the other Party's consent to an entity that acquires substantially all of the business or assets of the assigning Party, whether by merger, acquisition or otherwise; provided that the acquiring party agrees in a writing delivered to the non-assigning Party to assume all of the rights and obligations of the assigning Party under this Agreement. In addition, either Party shall have the right to assign this Agreement to an Affiliate, with the prior written consent of the other Party (which shall not be unreasonably withheld or delayed); provided that the assigning Party guarantees the performance of this Agreement by such Affiliate and such Affiliate agrees in a writing delivered to the non-assigning Party to assume all of the rights and obligations of the assigning Party under this Agreement; and further provided that if the non- assigning Party reasonably believes such assignment could result in material adverse tax consequences to the non-assigning Party, the non-assigning Party shall have no obligation to consent to the proposed assignment. For clarity, any assignment of this Agreement shall be without prejudice to any required review by the relevant competition law authorities. Subject to the foregoing, this Agreement shall inure to the benefit of each Party, its successors and permitted assigns. Any assignment of this Agreement in contravention of this Section 18.9 shall be null and void. 18.10 Change in Control. In the event of a Change in Control of Array in which the Acquirer is developing or commercializing [ * ] in the Field, any Development and Commercialization of a [ * ], Binimetinib and/or Encorafenib combination by the Parties shall be conducted subject to appropriate firewall procedures to segregate such activities (and the personnel conducting such activities) from the activities performed by or on behalf of Acquirer with respect to [ * ] it is developing or commercializing, to ensure that [ * ] is disclosed to employees of the Acquirer who are developing or commercializing the Acquirer's [ * ]. 18.11 Performance. Unless expressly otherwise provided hereunder, each Party or its Affiliates may perform its obligations hereunder through its Affiliates or Subcontractors, provided that such Party shall have entered into a written agreement (a "Subcontract") with its Subcontractors which shall be consistent with the terms and conditions of this Agreement, shall contain confidentiality provisions no less restrictive than those set forth in Article 10. Additionally, to the extent that such Subcontractor shall be responsible for performance of any Development activities undertaken in accordance with this Agreement, then the applicable Subcontract shall contain a certification that such Subcontractor has not been debarred, and is not subject to debarment, pursuant to Section 306 of the United States Federal Food, Drug and Cosmetics Act (or similar Laws of any other country), and is not the subject of a conviction described in such section. Notwithstanding the foregoing, the subcontracting Party (or Party whose Affiliate enters into a Subcontract) shall remain liable under this Agreement for the performance of all its obligations under this Agreement and shall be responsible for and liable for compliance by its Subcontractors with the applicable provisions of this Agreement. 83 [ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended. 18.12 No Partnership or Joint Venture. Nothing in this Agreement is intended, or shall be deemed, to establish a joint venture or partnership between Ono and Array. Neither Party to this Agreement shall have any express or implied right or authority to assume or create any obligations on behalf of, or in the name of, the other Party, or to bind the other Party to any contract, agreement or undertaking with any Third Party. 18.13 Interpretation. The captions to the several Articles and Sections of this Agreement are not a part of this Agreement, but are included for convenience of reference and shall not affect its meaning or interpretation. In this Agreement: (a) the word "including" shall be deemed to be followed by the phrase "without limitation" or like expression; (b) the singular shall include the plural and vice versa; and (c) masculine, feminine and neuter pronouns and expressions shall be interchangeable. Each accounting term used herein that is not specifically defined herein shall have the meaning given to it under generally accepted cost accounting principles, but only to the extent consistent with its usage and
"""

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

assistant: Any assignment of this Agreement in contravention of this Section 18.9 shall be null and void.