def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def cumsum(X):
        """
        Y[i] = sum(X[:i])
        """
        (m,) = X.shape
        s_state = te.placeholder((m + 1,), dtype="int32", name="state")
        s_init = te.compute((1,), lambda _: tvm.tir.const(0, "int32"))
        s_update = te.compute((m + 1,), lambda l: s_state[l - 1] + X[l - 1])
        return tvm.te.scan(s_init, s_update, s_state, inputs=[X], name="cumsum")