I went to GLAM night out tonight in the 7th floor of Newseum. Unfortunately, I left my bag there, under my seat (in the first row), or maybe in the elevator. It is a blue carry bag, with a smaller black bag in it, and a plastic bag in the black bag, containing some things I bought from Wiki-shop: three T-shirts, some Wikimedia Symbols, etc. So it is very important to me.
I wondered who's take charge of the GLAM night out and where can I get back my bag? Do I have to go to the Newseum again to find my bag or maybe someone will send my bag to the help desk of the venue?
Thanks a lot!

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Sincerely,
Shujen Chang