class_docstr: Mock logging handler to check for expected logs used by
  LoggingComparisonTestCase.
  
  Messages are available from an instance's ``messages`` dict, in
  order, indexed by a lowercase log level string (e.g., 'debug',
  'info', etc.).
class_docstr_tok: ["Mock","logging","handler","to","check","for","expected","logs","used","by","LoggingComparisonTestCase",".","Messages","are","available","from","an","instance","'s","``","messages","``","dict",",","in","order",",","indexed","by","a","lowercase","log","level","string","(","e.g.",",","'debug","'",",","'info","'",",","etc",".",")","."]
docstr: Store a message to the instance's messages dictionary
docstr_tok: ["Store","a","message","to","the","instance","'s","messages","dictionary"]
code: def emit(self, record):
      "Store a message to the instance's messages dictionary"
      self.acquire()
      try:
          self.messages[record.levelname].append(record.getMessage())
      finally:
          self.release()
  
file_path: holoviews/holoviews/tests/utils.py
imports: import logging
  import os
  import sys
  import param
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 2 for calling the MockLoggingHandler obj's underlying member method code with example usage: obj.emit(record) without return types