code: def scalar(tag, value, step, walltime=None):
      """Package data to one scalar.
      Args:
          tag (string): Data identifier
          value (float): Value of scalar
          step (int): Step of scalar
          walltime (int): Wall time of scalar
  
      Return:
          Package with format of record_pb2.Record
      """
      value = float(value)
      return Record(
          values=[
              Record.Value(
                  id=step, tag=tag, timestamp=walltime, value=value
              )
          ]
      )
  
imports: import numpy
  from PIL import Image
  from visualdl.proto.record_pb2 import Record
label_desc: Use image node_id 2 for calling a global function with example usage: scalar(tag, value, step, walltime) and returns: Record