code: def test_degree():
      t = tr.Degree(10)
      assert callable(t)
      g = Graph(x=x, a=a, e=e, y=y_gl)
      t(g)
      g = Graph(x=None, a=a, e=e, y=y_gl)
      t(g)
  
file_path: spektral/tests/test_transforms/test_transforms.py
imports: import numpy
  import scipy.sparse
  from spektral import transforms
  from spektral.data import Graph
label_desc: Use image node_id 4 for calling a global function with example usage: test_degree() without return types