docstr: EmitterGroup.block_all
docstr_tok: ["EmitterGroup.block_all"]
code: def test_group_block(self):
      """EmitterGroup.block_all"""
      grp = EmitterGroup(em1=Event, em2=Event)
  
      def cb(ev):
          self.result = 1
  
      grp.em1.connect(self.record_event)
      grp.em2.connect(self.record_event)
      grp.connect(cb)
  
      self.result = None
      grp.block_all()
      try:
          grp.em1()
          grp.em2()
          grp(type="test_event")
      finally:
          grp.unblock_all()
      assert self.result is None
  
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 3 for calling the TestGroups obj's underlying member method code with example usage: obj.test_group_block() without return types