input: Write a function named `render_page` that connects to MySQL, MongoDB, and PostgreSQL databases, queries data from each, and passes the results to a web template for display. The function should take a request object and return the rendered web page with the data from all three databases. The function should handle connecting to the databases, executing queries, and closing the connections.
  
  
  assert render_page('request_object') != None
  
output: def render_page(request):
      import mysql.connector
      from pymongo import MongoClient
      import psycopg2
      from jinja2 import Template
  
      # MySQL connection and query
      mysql_conn = mysql.connector.connect(user='user', password='password', host='127.0.0.1', database='mysql_db')
      mysql_cursor = mysql_conn.cursor()
      mysql_cursor.execute("SELECT * FROM table_name")
      mysql_data = mysql_cursor.fetchall()
      mysql_cursor.close()
      mysql_conn.close()
  
      # MongoDB connection and query
      mongo_client = MongoClient('mongodb://localhost:27017/')
      mongo_db = mongo_client['mongo_db']
      mongo_collection = mongo_db['collection_name']
      mongo_data = list(mongo_collection.find())
      mongo_client.close()
  
      # PostgreSQL connection and query
      pg_conn = psycopg2.connect(user='user', password='password', host='127.0.0.1', database='postgres_db')
      pg_cursor = pg_conn.cursor()
      pg_cursor.execute("SELECT * FROM table_name")
      pg_data = pg_cursor.fetchall()
      pg_cursor.close()
      pg_conn.close()
  
      # Render the web template with the data
      template_str = """
      <html>
      <head><title>Database Data</title></head>
      <body>
          <h1>MySQL Data</h1>
          <ul>
          {% for item in mysql_data %}
              <li>{{ item }}</li>
          {% endfor %}
          </ul>
          <h1>MongoDB Data</h1>
          <ul>
          {% for item in mongo_data %}
              <li>{{ item }}</li>
          {% endfor %}
          </ul>
          <h1>PostgreSQL Data</h1>
          <ul>
          {% for item in pg_data %}
              <li>{{ item }}</li>
          {% endfor %}
          </ul>
      </body>
      </html>
      """
      template = Template(template_str)
      rendered_page = template.render(mysql_data=mysql_data, mongo_data=mongo_data, pg_data=pg_data)
  
      return rendered_page