modeling under blender using the PyQt

Hello,
I would like to model under blender using the PyQt commands.
I started with a simple button that add Monkey object:

#Action du bouton import
self.import_btn.clicked.connect(self.SingleBrowse)

  def SingleBrowse(self):
        bpy.ops.mesh.primitive_monkey_add()

But there is nothing running and also I can not select something (object for example) from the scene …
Can you help me, please ?