input: Write a python function to retrieve the value associated with a given key from the objectMap dictionary.
  assert get_value("a") == "apple"
  assert get_value("d") == "date"
  assert get_value("e") == "eggplant"
  assert get_value("z") is None
output: def get_value(key):
      objectMap = {
          "a": "apple",
          "b": "banana",
          "c": "cherry",
          "d": "date",
          "e": "eggplant"
      }
      return objectMap.get(key)