input: Write a function to generate an HTML table from a list of lists.
  assert generate_table([['Name', 'Age'], ['John', '20'], ['Jane', '30'], ['Tom', '40']]) == '<table><tr><td>Name</td><td>Age</td></tr><tr><td>John</td><td>20</td></tr><tr><td>Jane</td><td>30</td></tr><tr><td>Tom</td><td>40</td></tr></table>'
  assert generate_table([['Fruit', 'Color'], ['Apple', 'Red'], ['Banana', 'Yellow'], ['Grapes', 'Green']]) == '<table><tr><td>Fruit</td><td>Color</td></tr><tr><td>Apple</td><td>Red</td></tr><tr><td>Banana</td><td>Yellow</td></tr><tr><td>Grapes</td><td>Green</td></tr></table>'
  assert generate_table([['Country', 'Capital'], ['France', 'Paris'], ['Japan', 'Tokyo'], ['Canada', 'Ottawa']]) == '<table><tr><td>Country</td><td>Capital</td></tr><tr><td>France</td><td>Paris</td></tr><tr><td>Japan</td><td>Tokyo</td></tr><tr><td>Canada</td><td>Ottawa</td></tr></table>'
output: def generate_table(data):
      html = '<table>'
      for row in data:
          html += '<tr>'
          for cell in row:
              html += f'<td>{cell}</td>'
          html += '</tr>'
      html += '</table>'
      return html