Print summary of GOEA plotting object.

def prt_summary(self, prt=sys.stdout):
        """Print summary of GOEA plotting object."""
        desc = "NtGoeaResults" if self.is_goterm else "namedtuple"
        prt.write("{N} GOEA results from {O}. P-values stored in {P}.\n".format(
            N=len(self.go2res), O=desc, P=self.pval_name))