docstr: Can still run even if the graph is without edges
docstr_tok: ["Can","still","run","even","if","the","graph","is","without","edges"]
code: def test_graph_with_no_edges(self):
      """Can still run even if the graph is without edges"""
  
      sm = StructureModel()
      nodes = [1, 2, 3]
      sm.add_nodes_from(nodes)
      sm.remove_edges_below_threshold(0.6)
  
      assert set(sm.nodes) == set(nodes)
      assert set(sm.edges) == set()
  
imports: import pytest
  from networkx.exception import NodeNotFound
  from causalnex.structure import StructureModel
label_desc: Use image node_id 4 for calling the TestStructureModelRemoveEdgesBelowThreshold obj's underlying member method code with example usage: obj.test_graph_with_no_edges() without return types