def is_valid_embedding(emb, source, target):
    """A simple (bool) diagnostic for minor embeddings.

    See :func:`diagnose_embedding` for a more detailed diagnostic / more information.

    Args:
        emb (dict): a dictionary mapping source nodes to arrays of target nodes
        source (graph or edgelist): the graph to be embedded
        target (graph or edgelist): the graph being embedded into

    Returns:
        bool: True if `emb` is valid.

    """
    for _ in diagnose_embedding(emb, source, target):
        return False
    return True