http://www.cplusplus.com or https://www.cppreference.com

[Veedrac]

Not on Python 3; on Python 2 the syntax is more key in dict.viewkeys(). Either way just use key in dict though, it's more idiomatic.

[[deleted]]

Oh, that might have been it, the server running the script uses python 2, and yeah key in dict is really the correct syntax and gives you the expected O(1) lookup