old_contents: import sys
  
  
  def import_class(import_str):
      """Returns a class from a string including module and class."""
  
      mod_str, _sep, class_str = import_str.rpartition(':')
      try:
          __import__(mod_str)
          return getattr(sys.modules[mod_str], class_str)
      except (ImportError, ValueError, AttributeError) as exc:
          # Convert it into an import error
          raise ImportError("Failed to import %s: %s" % (import_str, exc))
  
new_contents: import sys
  
  
  def import_class(import_str):
      """Returns a class from a string including module and class."""
  
      mod_str, _sep, class_str = import_str.rpartition(':')
      try:
          __import__(mod_str)
          return getattr(sys.modules[mod_str], class_str)
      except (ImportError, ValueError, AttributeError) as exc:
          # Convert it into an import error
          raise ImportError("Failed to import %s: %s" % (import_str, exc))
  
  
  class ignore_except(object):
      """Context manager to ignore all exceptions."""
  
      def __enter__(self):
          """Entry does nothing."""
  
          pass
  
      def __exit__(self, exc_type, exc_value, exc_traceback):
          """Return True to mark the exception as handled."""
  
          return True
  
subject: Add a context manager to ignore exceptions