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:
"""
SpinCo Group and escrow provider. ARTICLE IV LICENSES AND COVENANTS FROM SPINCO TO NUANCE Section 4.01. License Grants. (a) Patents. Subject to the terms and conditions of this Agreement, as of the Distribution Date, SpinCo hereby grants to Nuance and the members of the Nuance Group a worldwide, non-exclusive, fully paid-up, perpetual and irrevocable, transferable (subject to ARTICLE VIII), sublicensable (subject to Section 4.01(g)) license under the SpinCo Patents, solely to the extent that claims of the SpinCo Patents cover products or services of the Nuance Business in the Nuance Field of Use, together with natural extensions and evolutions thereof, in each case to make, have made use, sell, offer for sale, import and otherwise exploit such products and services, together with natural extensions and evolutions thereof. (b) Technology. Subject to the terms and conditions of this Agreement, as of the Distribution Date, SpinCo hereby grants to Nuance and the members of the Nuance Group a worldwide, non-exclusive, fully paid-up, perpetual and irrevocable, transferable (subject to ARTICLE VIII), sublicensable (subject to Section 4.01(g)) license to install, access, use, reproduce, perform, display, modify (including the right to create improvements and derivative works), further develop, sell, manufacture, distribute and market products and services based on, using or incorporating the SpinCo Shared Technology Assets within the Nuance Field of Use, together with natural extensions and evolutions thereof. (c) Other SpinCo Shared IP. Subject to the terms and conditions of this Agreement, as of the Distribution Date, SpinCo hereby grants to Nuance and the members of the Nuance Group a worldwide, non-exclusive, fully paid-up, perpetual and irrevocable, transferable (subject to ARTICLE VIII), sublicensable (subject to Section 4.01(g)) license to continue to use any SpinCo IP (other than SpinCo Patents, SpinCo Technology Assets, SpinCo Trademarks, SpinCo Domain Names and SpinCo Data), in each case solely as and to the extent that it is used by the Nuance Group in connection with products and services of the Nuance Business within the Nuance Field of Use, together with natural extensions and evolutions thereof. (d) Trademarks. The Parties acknowledge and agree that no rights are granted to the Nuance Group in this Agreement with respect to any Trademarks or Domain Names. (e) SpinCo Data. The Parties acknowledge and agree that certain rights and obligations with respect to the use or benefit of the Nuance Group of certain SpinCo Data shall be as provided in Schedule C. (f) OEM Technology. Notwithstanding the foregoing, the Parties acknowledge and agree that this Section 4.01 does not grant any rights or licenses to any OEM Technology, which is subject to certain separate agreements between the Parties, and to the 8 Source: CERENCE INC., 8-K, 10/2/2019 extent there is a conflict between this Agreement and such separate agreements, such separate agreements shall control. (g) Sublicenses. The licenses granted in Sections 4.01(a), (b) and (c) to the Nuance Group include the right to grant sublicenses within the scope of such licenses only to members of the Nuance Group and, without any further right to sublicense, to their respective (i) contractors, distributors, manufacturers and resellers, in each case solely for the benefit of the Nuance Business and (ii) end users and customers, in each case solely in connection with the use of products and services of the Nuance Business. Notwithstanding the forgoing, subject to Section 4.02(b) and ARTICLE VI, members of the Nuance Group may only sublicense the SpinCo Shared Technology Assets pursuant to terms and conditions as protective as those under which it licenses its own Technology of a similar nature and value, and in any event terms and conditions that provide for commercially reasonable protection for the source code, structure and other confidential and proprietary elements of the SpinCo Shared Technology Assets. The Nuance Group shall remain liable for any breach or default of the applicable terms and conditions of this Agreement by any of its sublicensees. Section 4.02. Other Covenants. (a) Nuance hereby acknowledges SpinCo's right, title and interest in and to the SpinCo IP. Nuance agrees that it will not (i) oppose, challenge, petition to cancel, contest or threaten in any way, or assist another party in opposing, challenging, petitioning to cancel, contesting or threatening in any way, any application or registration by SpinCo or its Affiliates or their respective licensees for any SpinCo IP, (ii) engage in any act, or purposefully omit to perform any act, that impairs or adversely affects the rights of SpinCo or any member of the SpinCo Group in and to any SpinCo IP or (iii)
"""

Extract the exact clause related to "Irrevocable Or Perpetual License" from the excerpt above.

assistant: Subject to the terms and conditions of this Agreement, as of the Distribution Date, SpinCo hereby grants to Nuance and the members of the Nuance Group a worldwide, non-exclusive, fully paid-up, perpetual and irrevocable, transferable (subject to ARTICLE VIII), sublicensable (subject to Section 4.01(g)) license to continue to use any SpinCo IP (other than SpinCo Patents, SpinCo Technology Assets, SpinCo Trademarks, SpinCo Domain Names and SpinCo Data), in each case solely as and to the extent that it is used by the Nuance Group in connection with products and services of the Nuance Business within the Nuance Field of Use, together with natural extensions and evolutions thereof.