class_docstr: Unit tests for :func:`networkx.generators.lattice.grid_2d_graph`
code: def test_periodic_multigraph(self):
      G = nx.grid_2d_graph(4, 2, periodic=True)
      H = nx.grid_2d_graph(
          4, 2, periodic=True, create_using=nx.MultiGraph()
      )
      assert list(G.edges()) == list(H.edges())
  
imports: from itertools import product
  import pytest
  import networkx
  from networkx.utils import edges_equal
label_desc: Use image node_id 8 for calling the TestGrid2DGraph obj's underlying member method code with example usage: obj.test_periodic_multigraph() without return types