class_docstr: Unit tests for the multi-source dialect of Dijkstra's shortest
  path algorithms.
class_docstr_tok: ["Unit","tests","for","the","multi-source","dialect","of","Dijkstra","'s","shortest","path","algorithms","."]
code: def test_path_no_sources(self):
      with pytest.raises(ValueError):
          nx.multi_source_dijkstra_path(nx.Graph(), {})
  
imports: import pytest
  import networkx
  from networkx.utils import pairwise
label_desc: Use image node_id 2 for calling the TestMultiSourceDijkstra obj's underlying member method code with example usage: obj.test_path_no_sources() without return types