code: def test_ismultigraph():
      g = dgl.graph([])
      g.add_nodes(10)
      assert g.is_multigraph == False
      g.add_edges([0], [0])
      assert g.is_multigraph == False
      g.add_edges([1], [2])
      assert g.is_multigraph == False
      g.add_edges([0, 2], [0, 3])
      assert g.is_multigraph == True
  
imports: import math
  import numbers
  import backend
  import dgl
  import networkx
  import numpy
  import pytest
  import scipy.sparse
  from dgl import DGLError
label_desc: Use image node_id 12 for calling a global function with example usage: test_ismultigraph() without return types