Run gene ontology enrichment analysis (GOEA).

def _init_objgoea(self, pop, assoc):
        """Run gene ontology enrichment analysis (GOEA)."""
        propagate_counts = not self.args.no_propagate_counts
        return GOEnrichmentStudy(pop, assoc, self.godag,
                                 propagate_counts=propagate_counts,
                                 relationships=False,
                                 alpha=self.args.alpha,
                                 pvalcalc=self.args.pvalcalc,
                                 methods=self.methods)