def atlas6():

    Atlas = graph_atlas_g()[0:208] # 208
    # remove isolated nodes, only connected graphs are left
    U = nx.Graph() # graph for union of all graphs in atlas
    for G in Atlas:
        zerodegree = [n for n in G if G.degree(n)==0]
        for n in zerodegree:
            G.remove_node(n)
        U = nx.disjoint_union(U, G)

    # list of graphs of all connected components
    C = nx.connected_component_subgraphs(U)

    UU = nx.Graph()
    # do quick isomorphic-like check, not a true isomorphism checker
    nlist = [] # list of nonisomorphic graphs
    for G in C:
        # check against all nonisomorphic graphs so far
        if not iso(G, nlist):
            nlist.append(G)
            UU = nx.disjoint_union(UU, G) # union the nonisomorphic graphs
    return UU
Return the atlas of all connected graphs of 6 nodes or less.
dataset/ETHPy150Open networkx/networkx/examples/drawing/atlas.py/atlas6