input: from typing import List
  
  def generate_html_table_for_top_books(genre: str, database_name: str) -> str:
      """Generate an HTML table displaying information about the top 10 bestselling
      books in a specific genre from a SQLite database.
      
      Parameters:
      genre (str): The genre of books to fetch.
      database_name (str): The name of the SQLite database file.
      
      Returns:
      str: An HTML table representation of the top 10 books.
      
      >>> generate_html_table_for_top_books('Fantasy', 'books.db')
      '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr><tr><td>...</td><td>...</td><td>Fantasy</td><td>...</td></tr></table>'
      """
output:     import sqlite3
  
      conn = sqlite3.connect(database_name)
      cursor = conn.cursor()
  
      query = f"SELECT Title, Author, Genre, Sales FROM Books WHERE Genre = ? ORDER BY Sales DESC LIMIT 10"
      cursor.execute(query, (genre,))
      rows = cursor.fetchall()
  
      conn.close()
  
      html_table = '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for row in rows:
          html_table += f'<tr><td>{row[0]}</td><td>{row[1]}</td><td>{row[2]}</td><td>{row[3]}</td></tr>'
      html_table += '</table>'
  
      return html_table