code: def test_spring_fixed_without_pos(self):
      G = nx.path_graph(4)
      pytest.raises(ValueError, nx.spring_layout, G, fixed=[0])
      pos = {0: (1, 1), 2: (0, 0)}
      pytest.raises(
          ValueError, nx.spring_layout, G, fixed=[0, 1], pos=pos
      )
      nx.spring_layout(G, fixed=[0, 2], pos=pos)
  
imports: import pytest
  import networkx
label_desc: Use image node_id 2 for calling the TestLayout obj's underlying member method code with example usage: obj.test_spring_fixed_without_pos() without return types