I believe the second to the last sentence in the third paragraph contains a few typos.
The single element pattern in our anonymous function implies, more specifically, that the the response it a list.
@jasullivan Thank you!
Another typo on Page 7 of the PDF:
If a pattern match is successful, it returns the data that matched the patter, which is “truthy.”
patter should be pattern
Good catch, I just fixed that, thanks 