code: def encode_chunks(l):  # noqa: E741
      """Encode a list of chunks into a single byte array, with lengths and magics.."""
      size = sum(16 + roundup(b.nbytes) for b in l)
      result = bytearray(size)
      offset = 0
      for b in l:
          result[offset : offset + 8] = magic_bytes
          offset += 8
          result[offset : offset + 8] = struct.pack("@q", b.nbytes)
          offset += 8
          result[offset : offset + bytelen(b)] = b
          offset += roundup(bytelen(b))
      return result
  
imports: import struct
  import sys
  import numpy
label_desc: Use image node_id 12 for calling a global function with example usage: encode_chunks(l) and returns: result