docstr: Emitter error handling
docstr_tok: ["Emitter","error","handling"]
code: def test_emitter_error_handling(self):
      """Emitter error handling"""
      em = EventEmitter(type="test_event")
      em.print_callback_errors = "never"
  
      def cb(ev):
          raise Exception("test")
  
      # first callback fails; second callback still runs.
      em.connect(self.record_event)
      em.connect(cb)
      self.result = None
      ev = em()
      self.assert_result(event=ev)
  
      # this time we should get an exception
      self.result = None
      em.ignore_callback_errors = False
      try:
          em()
          assert False, "Emission should have raised exception"
      except Exception as err:
          if str(err) != "test":
              raise
  
imports: import unittest
  import copy
  import functools
  from vispy.util.event import Event, EventEmitter
  from vispy.testing import run_tests_if_main, assert_raises, assert_equal
label_desc: Use image node_id 13 for calling the TestEmitters obj's underlying member method code with example usage: obj.test_emitter_error_handling() without return types