input: Write a python function to build an object with details including first name, last name, age, and address.
  assert build_object() == {
      "firstName": "John",
      "lastName": "Smith",
      "age": 40,
      "address": {
          "street": "123 Main Street",
          "city": "San Francisco",
          "state": "CA",
          "zipCode": "94105"
      }
  }
  assert build_object()["firstName"] == "John"
  assert build_object()["address"]["city"] == "San Francisco"
output: def build_object():
      return {
          "firstName": "John",
          "lastName": "Smith",
          "age": 40,
          "address": {
              "street": "123 Main Street",
              "city": "San Francisco",
              "state": "CA",
              "zipCode": "94105"
          }
      }