Function effective_color_map 

pub fn effective_color_map(
    slide: Option<&Slide>,
    layout: Option<&SlideLayout>,
    master: Option<&SlideMaster>,
) -> ColorMap

The p:clrMap in effect for a slide: its own p:clrMapOvr, else its layout’s, else the master’s. Every projection resolves scheme colours through this one predicate.