input: Write a function to connect and query data from three different databases (MySQL, MongoDB, and PostgreSQL) using their respective libraries, and then display the results on a web page. The function should execute specific queries for each database, fetch the results, close the connections, and render the results on the web page using a template.
  assert render_page(None)==None
  assert type(render_page(None))==type(None)
  assert 'data_mysql' in render_page(None).__dict__
  assert 'data_mongodb' in render_page(None).__dict__
  assert 'data_postgresql' in render_page(None).__dict__
  assert type(render_page(None).__dict__['data_mysql'])==dict
  assert type(render_page(None).__dict__['data_mongodb'])==dict
  assert type(render_page(None).__dict__['data_postgresql'])==dict
  assert len(render_page(None).__dict__['data_mysql'])>0
  assert len(render_page(None).__dict__['data_mongodb'])>0
  assert len(render_page(None).__dict__['data_postgresql'])>0
output: 
  def render_page(template):
      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='testdb')
      mysql_cursor = mysql_conn.cursor()
      mysql_cursor.execute("SELECT * FROM table_name LIMIT 1")
      mysql_data = mysql_cursor.fetchone()
      mysql_conn.close()
      data_mysql = {'mysql_data': mysql_data}
  
      # MongoDB connection and query
      mongo_client = MongoClient('localhost', 27017)
      mongo_db = mongo_client['testdb']
      mongo_collection = mongo_db['collection_name']
      mongo_data = mongo_collection.find_one()
      mongo_client.close()
      data_mongodb = {'mongodb_data': mongo_data}
  
      # PostgreSQL connection and query
      postgresql_conn = psycopg2.connect(host='localhost', database='testdb', user='postgres', password='password')
      postgresql_cursor = postgresql_conn.cursor()
      postgresql_cursor.execute("SELECT * FROM table_name LIMIT 1")
      postgresql_data = postgresql_cursor.fetchone()
      postgresql_conn.close()
      data_postgresql = {'postgresql_data': postgresql_data}
  
      return {'data_mysql': data_mysql, 'data_mongodb': data_mongodb, 'data_postgresql': data_postgresql}
  