input: Write a function to create a Python program that connects to three different databases (MySQL, MongoDB, and PostgreSQL), queries data from each, and then displays the results on a web page using their respective libraries. The function should handle the connection, query execution, and displaying of results on a web page.
  assert render_page(request)['data_mysql'] == 'expected_result_from_mysql_query'
  assert render_page(request)['data_mongodb'] == 'expected_result_from_mongodb_query'
  assert render_page(request)['data_postgresql'] == 'expected_result_from_postgresql_query'
output: def render_page(request):
      import mysql.connector
      from pymongo import MongoClient
      import psycopg2
      
      # MySQL connection and query
      mysql_conn = mysql.connector.connect(host='localhost', user='root', password='password', database='mysql_db')
      mysql_cursor = mysql_conn.cursor()
      mysql_cursor.execute("SELECT * FROM table_name")
      data_mysql = mysql_cursor.fetchall()
      mysql_conn.close()
      
      # MongoDB connection and query
      mongo_client = MongoClient('localhost', 27017)
      mongo_db = mongo_client['mongodb_db']
      mongo_collection = mongo_db['collection_name']
      data_mongodb = list(mongo_collection.find())
      mongo_client.close()
      
      # PostgreSQL connection and query
      postgresql_conn = psycopg2.connect(host='localhost', database='postgresql_db', user='postgres', password='password')
      postgresql_cursor = postgresql_conn.cursor()
      postgresql_cursor.execute("SELECT * FROM table_name")
      data_postgresql = postgresql_cursor.fetchall()
      postgresql_conn.close()
      
      return {
          'data_mysql': data_mysql,
          'data_mongodb': data_mongodb,
          'data_postgresql': data_postgresql
      }