code: def test_ext():
      def check(ext, packed):
          assert packb(ext) == packed
          assert unpackb(packed) == ext
  
      check(ExtType(0x42, b"Z"), b"\xd4\x42Z")  # fixext 1
      check(ExtType(0x42, b"ZZ"), b"\xd5\x42ZZ")  # fixext 2
      check(ExtType(0x42, b"Z" * 4), b"\xd6\x42" + b"Z" * 4)  # fixext 4
      check(ExtType(0x42, b"Z" * 8), b"\xd7\x42" + b"Z" * 8)  # fixext 8
      check(
          ExtType(0x42, b"Z" * 16), b"\xd8\x42" + b"Z" * 16
      )  # fixext 16
      # ext 8
      check(ExtType(0x42, b""), b"\xc7\x00\x42")
      check(ExtType(0x42, b"Z" * 255), b"\xc7\xff\x42" + b"Z" * 255)
      # ext 16
      check(ExtType(0x42, b"Z" * 256), b"\xc8\x01\x00\x42" + b"Z" * 256)
      check(
          ExtType(0x42, b"Z" * 0xFFFF),
          b"\xc8\xff\xff\x42" + b"Z" * 0xFFFF,
      )
      # ext 32
      check(
          ExtType(0x42, b"Z" * 0x10000),
          b"\xc9\x00\x01\x00\x00\x42" + b"Z" * 0x10000,
      )
  
imports: from pandas.io.msgpack import ExtType, packb, unpackb
label_desc: Use image node_id 5 for calling a global function with example usage: test_ext() without return types