code: def test_from_ram(self):
      pass
  
imports: import os
  import unittest
  import networkx
  import numpy
  import numpy.testing
  from pgmpy.models import SEM, SEMAlg, SEMGraph
label_desc: Use image node_id 4 for calling the TestSEM obj's underlying member method code with example usage: obj.test_from_ram() without return types