code: def test_bifurcations_1():
      myfield = basic_field()
      idx, parent, label = myfield.threshold_bifurcations()
      assert idx == 999
      assert parent == 0
  
imports: import numpy
  import numpy.random
  from numpy.testing import assert_array_equal
  from ..field import field_from_coo_matrix_and_data, field_from_graph_and_data
  from ..graph import wgraph_from_3d_grid
label_desc: Use image node_id 22 for calling a global function with example usage: test_bifurcations_1() without return types