# coding: utf-8
from __future__ import unicode_literals, print_function


class _Singleton(type):
    """ A metaclass that creates a Singleton base class when called. """
    _instances = {}

    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]


class Singleton(_Singleton(str('SingletonMeta'), (object,), {})):
    pass


def urlparse(url):
    try:
        from urlparse import urlparse
    except ImportError:
        from urllib.parse import urlparse

    return urlparse(url)