def METHOD_NAME(self):
    if self.source.startswith("s3://"):
        s3fs = lazy_module("s3fs")
        root = self.source.strip("s3://")
        s3map = s3fs.S3Map(root=root, s3=self.s3, check=False)
        store = s3map
    else:
        store = str(self.source)  # has to be a string in Python2.7 for local files
    return store