code: def pre_processing(data, context):
      """
      Empty node as a starting node since the DAG doesn't support multiple start nodes
      """
      if data is None:
          return data
      b64_data = []
      for row in data:
          input_data = row.get("data") or row.get("body")
          # Base64 encode the image to avoid the framework throwing
          # non json encodable errors
          b64_data.append(base64.b64encode(input_data).decode())
      return b64_data
  
label_desc: Use image node_id 1 for calling a global function with example usage: pre_processing(data, context) and returns: b64_data, data