What is the meaning of 'is' in this sentence?

I'm reading 'Black as Snow' by Nick Nolan and encountered this sentence.

"It's never easy." Libby laughed while clinking her cup with is. "But it works."

What's the meaning of 'is' in this sentence?

Plural 'i'? Typo?


Solution 1:

Yep! It's supposed to be 'his'. TYPO! Thought we got 'em all!

Solution 2:

It’s almost certainly a typo for his.