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:
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Company. Neither this Agreement nor any right hereunder or interest herein may be assigned or transferred by Consultant without the express written consent of Company. Company may assign this Agreement to any entity that succeeds to substantially all of the business or assets of Company. This Agreement shall be governed by the laws of the State of Texas, without reference to its conflicts of law principles. This Agreement may only be amended or modified by a writing signed by both parties. Waiver of any term or provision of this Agreement or forbearance to enforce any term or provision by either party shall not constitute a waiver as to any subsequent breach or failure of the same term or provision or a waiver of any other term or provision of this Agreement. In the event that any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, this Agreement shall continue in full force and effect without said provision, provided that no such severability shall be effective if it materially changes the economic benefit of this Agreement to either Company or Consultant. 10. Tax Matters. As follows: (a) Withholding. All forms of compensation referred to in this letter agreement are subject to reduction to reflect applicable withholding and payroll taxes and other deductions required by law. (b) Tax Advice. You are encouraged to obtain your own tax advice regarding your compensation from the Company. You agree that the Company does not have a duty to design its compensation policies in a manner that minimizes your tax liabilities, and you will not make any claim against the Company or the Board related to tax liabilities arising from your compensation. 11. Background Check and Authorization to Work. This offer of employment is contingent on the Company's completion of a satisfactory background check of you. Please note that because of employer regulations adopted in the Immigration Reform and Control Act of 1986, within three (3) business days of starting your new position you will need to present documentation demonstrating that you have authorization to work in the United States. If you have questions about this requirement, which applies to U.S. citizens and non-U.S. citizens alike, please let us know. 12. Interpretation, Amendment and Enforcement. This letter agreement will be effective as of July 1, 2018. This letter agreement and the Company's standard Proprietary Information and Inventions Agreement supersede and replace any prior agreements, representations or understandings (whether written, oral, implied or otherwise) between you and 844.KEY.CURE | www.kiromic.com PAGE 4 the Company and constitute the complete agreement between you and the Company regarding the subject matter set forth herein. This letter agreement may not be amended or modified, except by an express written agreement signed by both you and a duly authorized officer of the Company. 13. Arbitration Agreement. Any controversy or claim arising out of or relating to this agreement or breach thereof, shall be settled by binding arbitration controlled by the rules of the American Arbitration Association. The number of arbitrator(s) shall be one. The seat of arbitration shall be Houston, Texas. Texas law shall also apply to the extent necessary to fill any gaps created by the rules of the American Arbitration Association. The arbitration award shall be final and binding on the parties. Judgement of the award rendered by the arbitrator(s) may be entered into any court of competent jurisdiction. If any provision of this Arbitration Agreement is held illegal or unenforceable in a arbitration proceeding, such provision shall be severed and shall be inoperative, and the remainder of this Agreement shall remain operative and binding on the Parties. The arbitrator(s) shall have sole kompetenz-kompetenz regarding this Arbitration Agreement. 14. Severability. If any provision of this Agreement is held illegal or unenforceable in a judicial proceeding, such provision shall be severed and shall be inoperative, and the remainder of this Agreement shall remain operative and binding on the Parties. 15. Counterparts. This Agreement may be executed in any number of counterparts, each of which when so executed and delivered will be deemed an original, and all of which together will constitute one and the same agreement. 16. Entire Agreement. This Agreement and the documents referred to herein constitute the entire agreement and understanding of the parties with respect to the subject matter of this Agreement, and supersede all prior understandings and agreements, whether oral or written, between the parties hereto with respect to such subject matter. [SIGNATURE PAGE TO FOLLOW]
"""

Extract the exact clause related to "Effective Date" from the excerpt above.

assistant: This letter agreement will be effective as of July 1, 2018.