POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS that
STONEBRIDGE 2018, L.P. (the "Company") does hereby make,
constitute and appoint each of Jamison Yardley and
Jennifer Lee, acting individually, its true and lawful
attorney, to execute and deliver in its name and on its
behalf whether the Company is acting individually or as
representative of others, any and all filings required
to be made by the Company under the Securities Exchange
Act of 1934, (as amended, the "Act"), with respect to
securities which may be deemed to be beneficially owned
by the Company under the Act, giving and granting unto
each said attorney-in-fact power and authority to act in
the premises as fully and to all intents and purposes
as the Company might or could do if personally present
by one of its authorized signatories, hereby ratifying
and confirming all that said attorney-in-fact shall
lawfully do or cause to be done by virtue hereof.

THIS POWER OF ATTORNEY shall remain in full force and
effect until the earlier of (i)
May 20, 2022 and (ii) such time that it is revoked in
writing by the undersigned; provided that in the event
the attorney-in-fact ceases to be an employee of the
Company or its affiliates or ceases to perform the
function in connection with which he/she was appointed
attorney-in-fact prior to such time, this Power of
Attorney shall cease to have effect in relation to
such attorney-in-fact upon such cessation but shall
continue in full force and effect in relation to any
remaining attorneys-in-fact. The Company has the
unrestricted right unilaterally to revoke this Power
of Attorney.

This Power of Attorney shall be governed by, and
construed in accordance with, the laws of the State
of New York, without regard to rules of conflicts of law.

IN WITNESS WHEREOF, the undersigned has duly subscribed
these presents as of May 21, 2019.

STONEBRIDGE 2018, L.P.

By: Bridge Street Opportunity Advisors, L.L.C.,
its General Partner

By: /s/ William Y. Eng
Name: William Y. Eng
Title: Vice President