code: def test_get_keys():
      """Utils - Get Keys"""
      data = {
          "path": "ABC",
          "details": {"parent": {"path": "DEF"}},
          "empty_dict": {},
          "empty_list": [],
          "events": [{"path": "GHI"}],
      }
      assert_equal(
          {"ABC", "DEF", "GHI"}, set(utils.get_keys(data, "path"))
      )
      assert_equal(2, len(utils.get_keys(data, "path", max_matches=2)))
      assert_equal([], utils.get_keys({}, "path"))
  
file_path: streamalert/tests/unit/streamalert/shared/test_utils.py
imports: import json
  from nose.tools import assert_equal, assert_false
  from streamalert.shared import utils
  from streamalert.shared.normalize import Normalizer
label_desc: Use image node_id 6 for calling a global function with example usage: test_get_keys() without return types