'Return the configured django storage backend.'

@cached_property
def _storage(self):

    config = settings.VERIFY_STUDENT['SOFTWARE_SECURE']
    storage_class = config.get('STORAGE_CLASS', 'storages.backends.s3boto.S3BotoStorage')
    storage_kwargs = config.get('STORAGE_KWARGS', {})
    if ('AWS_ACCESS_KEY' in config):
        storage_kwargs['access_key'] = config['AWS_ACCESS_KEY']
    if ('AWS_SECRET_KEY' in config):
        storage_kwargs['secret_key'] = config['AWS_SECRET_KEY']
    if ('S3_BUCKET' in config):
        storage_kwargs['bucket'] = config['S3_BUCKET']
        storage_kwargs['querystring_expire'] = self.IMAGE_LINK_DURATION
    return get_storage(storage_class, **storage_kwargs)
