code: def test_str2duration(self):
      self.assertEqual(
          int(util.str2duration("30m").total_seconds()), 1800
      )
  
imports: import unittest
  from studio import util
  from random import randint
label_desc: Use image node_id 3 for calling the UtilTest obj's underlying member method code with example usage: obj.test_str2duration() without return types