A.Enum.split_with

You're seeing just the function split_with, go back to A.Enum module for more information.
Link to this function

split_with(enumerable, fun)

View Source

Specs

split_with(t(val), (val -> as_boolean(term()))) :: {[val], [val]}
when val: value()

Splits the enumerable in two lists according to the given function fun.

Mirrors Enum.split_with/2 with higher performance for Aja structures.