'Assures that the storage group with name of `host` exists.
If the storage group doesn\'t exist, create a one.'

def assure_storage_group(self, host):

    sg = self.client.get_storage_group(host.name)
    is_new_sg = False
    if (not sg.existed):
        sg = self.client.create_storage_group(host.name)
        is_new_sg = True
    return (sg, is_new_sg)
