code: def test_exceptions(self):
      cu = torch.jit.CompilationUnit(
          """
              def foo(cond):
                  if bool(cond):
                      raise ValueError(3)
                  return 1
          """
      )
  
      cu.foo(torch.tensor(0))
      with self.assertRaisesRegex(torch.jit.Error, "3"):
          cu.foo(torch.tensor(1))
  
      def foo(cond):
          a = 3
          if bool(cond):
              raise ArbitraryError(a, "hi")  # noqa: F821
              if 1 == 2:
                  raise ArbitraryError  # noqa: F821
          return a
  
      with self.assertRaisesRegex(
          RuntimeError, "undefined value ArbitraryError"
      ):
          torch.jit.script(foo)
  
      def exception_as_value():
          a = Exception()
          print(a)
  
      with self.assertRaisesRegex(
          RuntimeError, "cannot be used as a value"
      ):
          torch.jit.script(exception_as_value)
  
      @torch.jit.script
      def foo_no_decl_always_throws():
          raise RuntimeError("Hi")
  
      # function that has no declared type but always throws set to None
      output_type = next(
          foo_no_decl_always_throws.graph.outputs()
      ).type()
      self.assertTrue(str(output_type) == "NoneType")
  
      @torch.jit.script
      def foo_decl_always_throws():
          # type: () -> Tensor
          raise Exception("Hi")
  
      output_type = next(foo_decl_always_throws.graph.outputs()).type()
      self.assertTrue(str(output_type) == "Tensor")
  
      def foo():
          raise 3 + 4
  
      with self.assertRaisesRegex(
          RuntimeError, "must derive from BaseException"
      ):
          torch.jit.script(foo)
  
      # a escapes scope
      @torch.jit.script
      def foo():
          if 1 == 1:
              a = 1
          else:
              if 1 == 1:
                  raise Exception("Hi")
              else:
                  raise Exception("Hi")
          return a
  
      self.assertEqual(foo(), 1)
  
      @torch.jit.script
      def tuple_fn():
          raise RuntimeError("hello", "goodbye")
  
      with self.assertRaisesRegex(torch.jit.Error, "hello, goodbye"):
          tuple_fn()
  
      @torch.jit.script
      def no_message():
          raise RuntimeError
  
      with self.assertRaisesRegex(torch.jit.Error, "RuntimeError"):
          no_message()
  
file_path: pytorch/test/jit/test_exception.py
imports: from torch.testing._internal.common_utils import TestCase
  import torch
  from torch import nn
label_desc: Use image node_id 3 for calling the TestException obj's underlying member method code with example usage: obj.test_exceptions() and returns: a, a