code: def test_on_start_epoch(self):
      def example(state):
          return state
  
      state = "test"
      self.assertTrue(
          callbacks.on_start_epoch(example).on_start_epoch(state)
          == state
      )
  
imports: import unittest
  import torchbearer.callbacks
  import torchbearer
label_desc: Use image node_id 5 for calling the TestDecorators obj's underlying member method code with example usage: obj.test_on_start_epoch() and returns: state