Load standard graph validation sets

    For each size (from 6 to 32 graph nodes) the dataset consists of
    100 graphs drawn from the Erdős-Rényi ensemble with edge
    probability 50%.

def load_stdgraphs(size: int) -> List[nx.Graph]:
    """Load standard graph validation sets

    For each size (from 6 to 32 graph nodes) the dataset consists of
    100 graphs drawn from the Erdős-Rényi ensemble with edge
    probability 50%.
    """
    from pkg_resources import resource_stream

    if size < 6 or size > 32:
        raise ValueError('Size out of range.')

    filename = 'datasets/data/graph{}er100.g6'.format(size)
    fdata = resource_stream('quantumflow', filename)
    return nx.read_graph6(fdata)