old_contents: from bears.go.GoReturnsBear import GoReturnsBear
  from tests.LocalBearTestHelper import verify_local_bear
  
  good_file1 = """import "errors"
  
  func F() (*MyType, int, error) { return nil, 0, errors.New("foo") }"""\
  .splitlines(keepends=True)
  
  good_file2 = """package main
  
  import "os"
  
  func main() {
  \tf, _ := os.Open("foo")
  }""".splitlines(keepends=True)
  
  bad_file1 = """
  func F() (*MyType, int, error) { return errors.New("foo") }
  """.splitlines(keepends=True)
  
  bad_file2 = """
  package main
  
  func main() {
      f, _ := os.Open("foo")
      return nil, 0, errors.New("foo")
  }
  
  """.splitlines(keepends=True)
  
  a = ['import "errors"', '',
       'func F() (*MyType, int, error) { return nil, 0, errors.New("foo") }']
  b = ['package main', '', 'import "os"', '',
       'func main() {', '\tf, _ := os.Open("foo")', '}']
  
  GoReturnsBearTest = verify_local_bear(
      GoReturnsBear,
      (good_file1,
       good_file2,),
      (bad_file1, bad_file2,))
  
new_contents: from bears.go.GoReturnsBear import GoReturnsBear
  from tests.LocalBearTestHelper import verify_local_bear
  
  good_file1 = """import "errors"
  
  func F() (*MyType, int, error) { return nil, 0, errors.New("foo") }"""\
  .splitlines(keepends=True)
  
  good_file2 = """package main
  
  import "os"
  
  func main() {
  \tf, _ := os.Open("foo")
  }""".splitlines(keepends=True)
  
  bad_file1 = """
  func F() (*MyType, int, error) { return errors.New("foo") }
  """.splitlines(keepends=True)
  
  bad_file2 = """
  package main
  
  func main() {
      f, _ := os.Open("foo")
      return nil, 0, errors.New("foo")
  }
  
  """.splitlines(keepends=True)
  
  GoReturnsBearTest = verify_local_bear(
      GoReturnsBear,
      (good_file1,
       good_file2,),
      (bad_file1, bad_file2,))
  
subject: Remove unused variables