input: Write a python function to parse an XML string containing people's names and ages and generate an HTML table from it.
  assert generate_html_table("<xml><people><person><name>John Doe</name><age>30</age></person><person><name>Jane Smith</name><age>25</age></person></people></xml>") == '''<html>
   <head>
    <title>People</title>
   </head>
   <body>
    <h1>People</h1>
    <table>
     <thead>
      <tr>
       <th>Name</th>
       <th>Age</th>
      </tr>
     </thead>
     <tbody>
      <tr><td>John Doe</td><td>30</td></tr>
      <tr><td>Jane Smith</td><td>25</td></tr>
     </tbody>
    </table>
   </body>
  </html>
  '''
  assert generate_html_table("<xml><people><person><name>Alice Brown</name><age>22</age></person><person><name>Bob Johnson</name><age>34</age></person></people></xml>") == '''<html>
   <head>
    <title>People</title>
   </head>
   <body>
    <h1>People</h1>
    <table>
     <thead>
      <tr>
       <th>Name</th>
       <th>Age</th>
      </tr>
     </thead>
     <tbody>
      <tr><td>Alice Brown</td><td>22</td></tr>
      <tr><td>Bob Johnson</td><td>34</td></tr>
     </tbody>
    </table>
   </body>
  </html>
  '''
output: def generate_html_table(xml_string):
      import xml.etree.ElementTree as ET
  
      root = ET.fromstring(xml_string)
      people = root.find('people')
  
      rows = []
      for person in people:
          name = person.find('name').text
          age = person.find('age').text
          rows.append(f"<tr><td>{name}</td><td>{age}</td></tr>")
  
      html = '''<html>
   <head>
    <title>People</title>
   </head>
   <body>
    <h1>People</h1>
    <table>
     <thead>
      <tr>
       <th>Name</th>
       <th>Age</th>
      </tr>
     </thead>
     <tbody>'''
      
      html += ''.join(rows)
  
      html += '''
     </tbody>
    </table>
   </body>
  </html>
  '''
      return html