The story
In reference to the phrase don't call us, we'll call you, supposed to be a common dismissal from Hollywood film auditions and hiring organizations, but used here regarding function calls.
Etymology from Wiktionary, CC BY-SA 4.0.
Hollywood principle
Today it means: A software design principle, stated as "Don't call us, we'll call you", that assists in the development of code with high cohesion and low coupling that is easier to debug, maintain and test. Full definition →