docs: def primary_from_name(self, tax_name):
          """
          Return tax_id and primary tax_name corresponding to tax_name.
          """
          names = self.names
  
          s1 = select([names.c.tax_id, names.c.is_primary],
                      names.c.tax_name == tax_name)
  
          log.debug(str(s1))
  
          res = s1.execute().fetchone()
          if res:
              tax_id, is_primary = res
          else:
              msg = '"{}" not found in names.tax_names'.format(tax_name)
              raise ValueError(msg)
  
          if not is_primary:
              s2 = select([names.c.tax_name],
                          and_(names.c.tax_id == tax_id,
                               names.c.is_primary))
              tax_name = s2.execute().fetchone()[0]
  
          return tax_id, tax_name, bool(is_primary)