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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _GetEventIdentifiers(self, event):
 """Retrieves different identifiers of the event. Every event contains event data, which consists of attributes and values. These attributes and values can be represented as a string and used for sorting and uniquely identifying events. This function determines multiple identifiers: * an identifier of the attributes and values without the timestamp description (or usage). This is referred to as the MACB group identifier. * an identifier of the attributes and values including the timestamp description (or usage). This is referred to as the event content identifier. The identifier without the timestamp description can be used to group events that have the same MACB (modification, access, change, birth) timestamps. The PsortEventHeap will store these events individually and relies on PsortMultiProcessEngine to do the actual grouping of events. Args: event (EventObject):
 event. Returns: tuple: containing: str: identifier of the event MACB group or None if the event cannot be grouped. str: identifier of the event content. """

    attributes = []

    attribute_string = 'data_type: {0:s}'.format(event.data_type)
    attributes.append(attribute_string)

    for attribute_name, attribute_value in sorted(event.GetAttributes()):
      if attribute_name in self._IDENTIFIER_EXCLUDED_ATTRIBUTES:
        continue

      if not attribute_value:
        continue

      if attribute_name == 'pathspec':
        attribute_value = attribute_value.comparable

      elif isinstance(attribute_value, dict):
        attribute_value = sorted(attribute_value.items())

      elif isinstance(attribute_value, set):
        attribute_value = sorted(list(attribute_value))

      elif isinstance(attribute_value, py2to3.BYTES_TYPE):
        attribute_value = repr(attribute_value)

      try:
        attribute_string = '{0:s}: {1!s}'.format(
            attribute_name, attribute_value)
      except UnicodeDecodeError:
        logger.error('Failed to decode attribute {0:s}'.format(
            attribute_name))
      attributes.append(attribute_string)

    # The 'atime', 'ctime', 'crtime', 'mtime' are included for backwards
    # compatibility with the filestat parser.
    if event.timestamp_desc in (
        'atime', 'ctime', 'crtime', 'mtime',
        definitions.TIME_DESCRIPTION_LAST_ACCESS,
        definitions.TIME_DESCRIPTION_CHANGE,
        definitions.TIME_DESCRIPTION_CREATION,
        definitions.TIME_DESCRIPTION_MODIFICATION):
      macb_group_identifier = ', '.join(attributes)
    else:
      macb_group_identifier = None

    attributes.insert(0, event.timestamp_desc)
    content_identifier = ', '.join(attributes)

    return macb_group_identifier, content_identifier