code: def alloc_mem(bytes):
      chunks = 10
      mem = []
      bytes_per_chunk = bytes // 8 // chunks
      for _ in range(chunks):
          mem.append([0] * bytes_per_chunk)
      return mem
  
imports: import sys
  import threading
  import pytest
  import ray
  from ray.tests.test_memory_pressure import allocate_memory, Leaker, get_additional_bytes_to_reach_memory_usage_pct, memory_usage_threshold, memory_monitor_refresh_ms
label_desc: Use image node_id 2 for calling a global function with example usage: alloc_mem(bytes) and returns: mem