code: def test_recordio_pack_label():
      N = 255
  
      for i in range(1, N):
          for j in range(N):
              content = "".join(
                  random.choice(string.ascii_uppercase + string.digits)
                  for _ in range(j)
              )
              content = content.encode("utf-8")
              label = np.random.uniform(size=i).astype(np.float32)
              header = (0, label, 0, 0)
              s = mx.recordio.pack(header, content)
              rheader, rcontent = mx.recordio.unpack(s)
              assert (label == rheader.label).all()
              assert content == rcontent
  
imports: import sys
  import mxnet
  import numpy
  import random
  import string
label_desc: Use image node_id 3 for calling a global function with example usage: test_recordio_pack_label() without return types