How to use the gcsfs.core.GCSFileSystem.load_tokens function in gcsfs

raise FileNotFoundError
            elif status == 403:
                raise IOError("Forbidden: %s\n%s" % (path, msg))
            elif status == 502:
                raise ProxyError()
            elif "invalid" in str(msg):
                raise ValueError("Bad Request: %s\n%s" % (path, msg))
            elif error:
                raise HttpError(error)
            elif status:
                raise HttpError({"code": status})
            else:
                raise RuntimeError(msg)


GCSFileSystem.load_tokens()


class GCSFile(fsspec.spec.AbstractBufferedFile):
    def __init__(
        self,
        gcsfs,
        path,
        mode="rb",
        block_size=DEFAULT_BLOCK_SIZE,
        autocommit=True,
        cache_type="readahead",
        cache_options=None,
        acl=None,
        consistency="md5",
        metadata=None,
        content_type=None,

consistency: None or str
            If None, use default for this instance
        """
        if block_size is None:
            block_size = self.default_block_size
        const = consistency or self.consistency
        return GCSFile(self, path, mode, block_size, consistency=const,
                       metadata=metadata, acl=acl, autocommit=autocommit)

    def __setstate__(self, state):
        self.__dict__.update(state)
        self.dircache = {}
        self.connect(self.token)


GCSFileSystem.load_tokens()


class GCSFile(fsspec.spec.AbstractBufferedFile):

    def __init__(self, gcsfs, path, mode='rb', block_size=DEFAULT_BLOCK_SIZE,
                 acl=None, consistency='md5', metadata=None,
                 autocommit=True):
        """
        Open a file.

        Parameters
        ----------
        gcsfs: instance of GCSFileSystem
        path: str
            location in GCS, like 'bucket/path/to/file'
        mode: str