code: def atlas6():
      """Return the atlas of all connected graphs with at most 6 nodes"""
  
      Atlas = nx.graph_atlas_g()[
          3:209
      ]  # 0, 1, 2 => no edges. 208 is last 6 node graph
      U = nx.Graph()  # graph for union of all graphs in atlas
      for G in Atlas:
          # check if connected
          if nx.number_connected_components(G) == 1:
              # check if isomorphic to a previous graph
              if not GraphMatcher(U, G).subgraph_is_isomorphic():
                  U = nx.disjoint_union(U, G)
      return U
  
imports: import random
  import matplotlib.pyplot
  import networkx
label_desc: Use image node_id 1 for calling a global function with example usage: atlas6() and returns: U