code: def memory_used():
      data = psutil.virtual_memory().used / (1024 * 1024)  # in MB
      system_metrics.append(Metric("MemoryUsed", data, "MB", dimension))
  
file_path: serve/ts/metrics/system_metrics.py
imports: import logging
  import types
  from builtins import str
  import psutil
  from ts.metrics.dimension import Dimension
  from ts.metrics.metric import Metric
label_desc: Use image node_id 2 for calling a global function with example usage: memory_used() without return types