def METHOD_NAME(blockette, identifier):
    """
    Returns an X-Path String to a blockette with the correct identifier.
    """
    try:
        identifier = int(identifier)
    except Exception:
        msg = 'X-Path identifier needs to be an integer.'
        raise TypeError(msg)
    abbr_path = '/xseed/abbreviation_dictionary_control_header/'
    end_of_path = '[text()="%s"]/parent::*'
    if blockette == 30:
        return abbr_path + \
            'data_format_dictionary/data_format_identifier_code' + \
            end_of_path % identifier
    elif blockette == 31:
        return abbr_path + \
            'comment_description/comment_code_key' + \
            end_of_path % identifier
    elif blockette == 33:
        return abbr_path + \
            'generic_abbreviation/abbreviation_lookup_code' + \
            end_of_path % identifier
    elif blockette == 34:
        return abbr_path + \
            'units_abbreviations/unit_lookup_code' + \
            end_of_path % identifier
    # All dictionary blockettes.
    elif blockette == 'dictionary':
        return abbr_path + \
            '*/response_lookup_key' + \
            end_of_path % identifier
    msg = 'XPath for blockette %d not implemented yet.' % blockette
    raise NotImplementedError(msg)