code: def test_node_flag_setter():
      try:
          new_node = node.Node(name=0, category="FUNCTION")
          new_node.flag = 10
      except:
          new_node = node.Node(name=0, category="FUNCTION")
  
      assert new_node.flag is True
  
imports: import numpy
  from opytimizer.core import node
label_desc: Use image node_id 15 for calling a global function with example usage: test_node_flag_setter() without return types