如何从以下JSON提要中获取电子邮件地址？

import json

# 假设以下是包含JSON数据的字符串
json_data = '''
{
  "name": "John Doe",
  "email": "johndoe@example.com",
  "contact": {
    "emailAddress": "johndoe@gmail.com",
    "phone": "1234567890"
  }
}
'''

# 解析JSON数据
data = json.loads(json_data)

# 获取电子邮件地址
email = None

if "email" in data:
    email = data["email"]
elif "emailAddress" in data["contact"]:
    email = data["contact"]["emailAddress"]

# 验证电子邮件地址的有效性
if email is not None:
    # 进行电子邮件地址的验证操作

# 打印提取的电子邮件地址
print(email)