code: def p_null_assignment(self, t):
      '''null_assignment : IDENT EQ NULL'''
      self.accu.add(Term('obs_vlabel', [self.name,"gen(\""+t[1]+"\")","0"])f p_null_assignment(self, t):
      '''null_assignment : IDENT EQ NULL'''
      self.accu.add(Term('obs_vlabel', [self.name,"gen(\""+t[1]+"\")","0"]))
docs: null_assignment : IDENT EQ NULL