code: def test_jpeg3(h, f):
      """JPEG data in JFIF or Exif format"""
      if h[6:10] in (b"JFIF", b"Exif") or h[:2] == b"\xff\xd8":
          return "jpeg"
  
imports: from imghdr import tests
label_desc: Use image node_id 3 for calling a global function with example usage: test_jpeg3(h, f) and returns: str