docstr: EmitterGroup.disconnect
docstr_tok: ["EmitterGroup.disconnect"]
code: def test_group_disconnect(self):
      """EmitterGroup.disconnect"""
      grp = EmitterGroup(em1=Event)
  
      assert len(grp.em1.callbacks) == 0, grp.em1.callbacks
      grp.connect(self.record_event)
      assert len(grp.em1.callbacks) == 1
      grp.add(em2=Event)
      assert len(grp.em2.callbacks) == 1
      grp.disconnect()
      assert len(grp.em1.callbacks) == 0
      assert len(grp.em2.callbacks) == 0
  
imports: import unittest
  import copy
  from vispy.util.event import Event, EventEmitter, EmitterGroup
  from vispy.util import use_log_level
  from vispy.testing import run_tests_if_main, assert_true, assert_raises
label_desc: Use image node_id 5 for calling the TestGroups obj's underlying member method code with example usage: obj.test_group_disconnect() without return types