def seqcontains(seq, subseq):
    """
    returns False if subseq is not contained in seq
    returns the (start, end) indices if seq contains subseq, so that
    >>> seq, subseq = range(10), [3, 4, 5]
    >>> indices = seqcontains(seq, subseq)
    >>> assert seq[indices[0]:indices[1]] == subseq
    """
    for i in range(len(seq) - len(subseq) + 1):
        for j in range(len(subseq)):
            if seq[i + j] != subseq[j]:
                break
        else:
            return i, i + len(subseq)
    return False
