26     def exists_validvals(self, varname, varlist, validlist):  argument
27         self.assertIn(varname, varlist)
28         self.assertIn(varlist[varname], validlist)
29         return varlist[varname]
31     def exists_yes_no(self, varname, varlist):  argument
32         return self.exists_validvals(varname, varlist, ["yes", "no"])
34     def exists_nonempty(self, varname, varlist):  argument
35         self.assertIn(varname, varlist)
36         self.assertGreater(len(varlist[varname]), 0)
37         return varlist[varname]
39     def exists_integer(self, varname, varlist, base=10):  argument
41         self.assertIn(varname, varlist)
43             val = int(varlist[varname], base)
45             self.fail("%s (%s) is not an integer" % (varname, varlist[varname]))