Function phStatus(ph, a1, a2)  maps a pair of star-alleles to a MetabolizerStatus according to the lists
       defined in the PhenotypeTemplate record.
ph – Phenotype: Must contain arrays
          poor, intermediate, rapid, and ultra.a1 – String: First allele identifier.a2 – String: Second allele identifier.s – MetabolizerStatus: One of
          Poor, Intermediate, Normal,
          Rapid, or Ultra.s = Normal.ph.poor, set s = Poor.ph.rapid, set s = Rapid.ph.intermediate, set s = Intermediate.ph.ultra, set s = Ultra.Normal.function phStatus input Phenotype ph; input String a1; input String a2; output MetabolizerStatus s; end phStatus;