Коннект с MySQL

* В Python классы могут быть вложенными

import MySQLdb

# Singleton

class Singleton:
  def __init__(self, cls):
    self.cls = cls
    self.instance = None
  def __call__(self, *args, **kwds):
    if self.instance == None:
      self.instance = self.cls(*args, **kwds)
    return self.instance

@Singleton
class Database:
  connection = None
  def get_connection(self):
    if self.connection is None:
      self.connection = MySQLdb.connect(
        host="localhost", user="root", passwd="111", db="test")
    return self.connection

db1 = Database().get_connection()
db2 = Database().get_connection()