code: def output_keys_for(output_features):
      keys = []
      for feature in output_features:
          name = feature["name"]
          if feature["type"] == "category":
              keys.append(f"{name}_predictions")
              keys.append(f"{name}_probability")
              keys.append(f"{name}_probabilities")
              for category in feature[DECODER]["idx2str"]:
                  keys.append(f"{name}_probabilities_{category}")
  
          elif feature["type"] == "number":
              keys.append(f"{name}_predictions")
          else:
              raise NotImplementedError
      return keys
  
file_path: ludwig/tests/integration_tests/test_server.py
imports: import json
  import logging
  import os
  import sys
  import numpy
  import pytest
  from ludwig.api import LudwigModel
  from ludwig.constants import BATCH_SIZE, DECODER, TRAINER
  from ludwig.serve import server
  from ludwig.utils.data_utils import read_csv
  from tests.integration_tests.utils import audio_feature, category_feature, generate_data, image_feature, LocalTestBackend, number_feature, text_feature
label_desc: Use image node_id 3 for calling a global function with example usage: output_keys_for(output_features) and returns: keys