8. The storage medium of claim 7 , wherein the method further comprises: obtaining a second model representation of a second predictive model; selecting a second model implementation for the second model representation; and associating each of the selected model implementations with a node in a directed graph, wherein for one or more ordered pairs of nodes in the graph the prediction output of a model implementation associated with a tail node in the pair serves as input to a model implementation associated with a head node in the pair.
8. The storage medium of claim 7 , wherein the method further comprises: obtaining a second model representation of a second predictive model; selecting a second model implementation for the second model representation; and associating each of the selected model implementations with a node in a directed graph, wherein for one or more ordered pairs of nodes in the graph the prediction output of a model implementation associated with a tail node in the pair serves as input to a model implementation associated with a head node in the pair. 9. The storage medium of claim 8 , wherein causing execution of the selected model implementation comprises: executing each model implementation in an order prescribed by the directed graph.