如何从google geocoding api的xml响应中检索邮政编码？

import xml.etree.ElementTree as ET

# 解析XML响应
xml_response = """
<GeocodeResponse>
  <result>
    <address_component>
      <long_name>1600</long_name>
      <short_name>1600</short_name>
      <type>street_number</type>
    </address_component>
    <address_component>
      <long_name>Pennsylvania Avenue Northwest</long_name>
      <short_name>Pennsylvania Ave NW</short_name>
      <type>route</type>
    </address_component>
    <address_component>
      <long_name>Washington</long_name>
      <short_name>Washington</short_name>
      <type>locality</type>
      <type>political</type>
    </address_component>
    <address_component>
      <long_name>District of Columbia</long_name>
      <short_name>DC</short_name>
      <type>administrative_area_level_1</type>
      <type>political</type>
    </address_component>
    <address_component>
      <long_name>United States</long_name>
      <short_name>US</short_name>
      <type>country</type>
      <type>political</type>
    </address_component>
    <address_component>
      <long_name>20500</long_name>
      <short_name>20500</short_name>
      <type>postal_code</type>
    </address_component>
    <geometry>
      <location>
        <lat>38.8976633</lat>
        <lng>-77.0365739</lng>
      </location>
      <location_type>ROOFTOP</location_type>
      <viewport>
        <southwest>
          <lat>38.8963143197085</lat>
          <lng>-77.0379228802915</lng>
        </southwest>
        <northeast>
          <lat>38.8990122802915</lat>
          <lng>-77.0352249197085</lng>
        </northeast>
      </viewport>
    </geometry>
  </result>
  <status>OK</status>
</GeocodeResponse>
"""

root = ET.fromstring(xml_response)

# 遍历XML节点，找到包含邮政编码信息的节点
postal_code = None
for address_component in root.iter('address_component'):
    for type_element in address_component.iter('type'):
        if type_element.text == 'postal_code':
            postal_code = address_component.find('long_name').text
            break

# 输出检索到的邮政编码
print("Postal Code:", postal_code)