code: def test_str_isalpha(self):
      self.run_test(
          "def str_isalpha(s, t, u): return s.isalpha(), t.isalpha(), u.isalpha()",
          "e",
          "1",
          "",
          str_isalpha=[str, str, str],
      )
      self.run_test(
          "def str_isalpha_a(s, t): return s[0].isalpha(), t[0].isalpha()",
          "e",
          "1",
          str_isalpha_a=[str, str],
      )
  
imports: from pythran.tests import TestEnv
  from pythran.typing import List
  import unittest
label_desc: Use image node_id 39 for calling the TestStr obj's underlying member method code with example usage: obj.test_str_isalpha() without return types