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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def connection(cls):
 """HTTP connection for the current thread"""

        local = cls._threadlocal
        if not getattr(local, 'connection', None):
            # Make sure these variables are no longer affected by other threads.
            local.user = cls.user
            local.password = cls.password
            local.site = cls.site
            local.timeout = cls.timeout
            local.headers = cls.headers
            local.format = cls.format
            local.version = cls.version
            local.url = cls.url
            if cls.site is None:
                raise ValueError("No shopify session is active")
            local.connection = ShopifyConnection(
                cls.site, cls.user, cls.password, cls.timeout, cls.format)
        return local.connection