# Buggy code
def __init__(
    self,
    locale=None,
    domain=None,
    header_comment=DEFAULT_HEADER,
    project=None,
    version=None,
    copyright_holder=None,
    msgid_bugs_address=None,
    creation_date=None,
    revision_date=None,
    last_translator=None,
    language_team=None,
    charset=None,
    fuzzy=True,
):
    """Initialize the catalog object.

    :param locale: the locale identifier or `Locale` object, or `None`
                   if the catalog is not bound to a locale (which basically
                   means it's a template)
    :param domain: the message domain
    :param header_comment: the header comment as string, or `None` for the
                           default header
    :param project: the project's name
    :param version: the project's version
    :param copyright_holder: the copyright holder of the catalog
    :param msgid_bugs_address: the email address or URL to submit bug
                               reports to
    :param creation_date: the date the catalog was created
    :param revision_date: the date the catalog was revised
    :param last_translator: the name and email of the last translator
    :param language_team: the name and email of the language team
    :param charset: the encoding to use in the output (defaults to utf-8)
    :param fuzzy: the fuzzy bit on the catalog header
    """
    self.domain = domain
    if locale:
        locale = Locale.parse(locale)
    self.locale = locale
    self._header_comment = header_comment
    self._messages = odict()

    self.project = project or "PROJECT"
    self.version = version or "VERSION"
    self.copyright_holder = copyright_holder or "ORGANIZATION"
    self.msgid_bugs_address = msgid_bugs_address or "EMAIL@ADDRESS"

    self.last_translator = last_translator or "FULL NAME <EMAIL@ADDRESS>"
    """Name and email address of the last translator."""
    self.language_team = language_team or "LANGUAGE <LL@li.org>"
    """Name and email address of the language team."""

    self.charset = charset or "utf-8"

    if creation_date is None:
        creation_date = datetime.now(LOCALTZ)
    elif isinstance(creation_date, datetime) and not creation_date.tzinfo:
        creation_date = creation_date.replace(tzinfo=LOCALTZ)
    self.creation_date = creation_date
    if revision_date is None:
        revision_date = "YEAR-MO-DA HO:MI+ZONE"
    elif isinstance(revision_date, datetime) and not revision_date.tzinfo:
        revision_date = revision_date.replace(tzinfo=LOCALTZ)
    self.revision_date = revision_date
    self.fuzzy = fuzzy

    self.obsolete = odict()  # Dictionary of obsolete messages
    self._num_plurals = None
    self._plural_expr = None


# Traceback (babel.core.UnknownLocaleError)
Traceback (most recent call last):
File "/usr/local/bin/pybabel", line 11, in <module>
sys.exit(main())
File "/usr/local/lib/python3.5/dist-packages/babel/messages/frontend.py", line 908, in main
return CommandLineInterface().run(sys.argv)
File "/usr/local/lib/python3.5/dist-packages/babel/messages/frontend.py", line 832, in run
return cmdinst.run()
File "/usr/local/lib/python3.5/dist-packages/babel/messages/frontend.py", line 182, in run
self._run_domain(domain)
File "/usr/local/lib/python3.5/dist-packages/babel/messages/frontend.py", line 221, in _run_domain
catalog = read_po(infile, locale)
File "/usr/local/lib/python3.5/dist-packages/babel/messages/pofile.py", line 331, in read_po
parser.parse(fileobj)
File "/usr/local/lib/python3.5/dist-packages/babel/messages/pofile.py", line 265, in parse
self._process_comment(line)
File "/usr/local/lib/python3.5/dist-packages/babel/messages/pofile.py", line 224, in _process_comment
self._finish_current_message()
File "/usr/local/lib/python3.5/dist-packages/babel/messages/pofile.py", line 164, in _finish_current_message
self._add_message()
File "/usr/local/lib/python3.5/dist-packages/babel/messages/pofile.py", line 158, in _add_message
self.catalog[msgid] = message
File "/usr/local/lib/python3.5/dist-packages/babel/messages/catalog.py", line 596, in __setitem__
self.mime_headers = _parse_header(message.string).items()
File "/usr/local/lib/python3.5/dist-packages/babel/messages/catalog.py", line 399, in _set_mime_headers
self.locale = Locale.parse(value)
File "/usr/local/lib/python3.5/dist-packages/babel/core.py", line 331, in parse
raise UnknownLocaleError(input_id)
babel.core.UnknownLocaleError: unknown locale 'sr_SP'

# Fixed code
def __init__(
    self,
    locale=None,
    domain=None,
    header_comment=DEFAULT_HEADER,
    project=None,
    version=None,
    copyright_holder=None,
    msgid_bugs_address=None,
    creation_date=None,
    revision_date=None,
    last_translator=None,
    language_team=None,
    charset=None,
    fuzzy=True,
):
    """Initialize the catalog object.

    :param locale: the locale identifier or `Locale` object, or `None`
                   if the catalog is not bound to a locale (which basically
                   means it's a template)
    :param domain: the message domain
    :param header_comment: the header comment as string, or `None` for the
                           default header
    :param project: the project's name
    :param version: the project's version
    :param copyright_holder: the copyright holder of the catalog
    :param msgid_bugs_address: the email address or URL to submit bug
                               reports to
    :param creation_date: the date the catalog was created
    :param revision_date: the date the catalog was revised
    :param last_translator: the name and email of the last translator
    :param language_team: the name and email of the language team
    :param charset: the encoding to use in the output (defaults to utf-8)
    :param fuzzy: the fuzzy bit on the catalog header
    """
    self.domain = domain
    self.locale = locale
    self._header_comment = header_comment
    self._messages = odict()

    self.project = project or "PROJECT"
    self.version = version or "VERSION"
    self.copyright_holder = copyright_holder or "ORGANIZATION"
    self.msgid_bugs_address = msgid_bugs_address or "EMAIL@ADDRESS"

    self.last_translator = last_translator or "FULL NAME <EMAIL@ADDRESS>"
    """Name and email address of the last translator."""
    self.language_team = language_team or "LANGUAGE <LL@li.org>"
    """Name and email address of the language team."""

    self.charset = charset or "utf-8"

    if creation_date is None:
        creation_date = datetime.now(LOCALTZ)
    elif isinstance(creation_date, datetime) and not creation_date.tzinfo:
        creation_date = creation_date.replace(tzinfo=LOCALTZ)
    self.creation_date = creation_date
    if revision_date is None:
        revision_date = "YEAR-MO-DA HO:MI+ZONE"
    elif isinstance(revision_date, datetime) and not revision_date.tzinfo:
        revision_date = revision_date.replace(tzinfo=LOCALTZ)
    self.revision_date = revision_date
    self.fuzzy = fuzzy

    self.obsolete = odict()  # Dictionary of obsolete messages
    self._num_plurals = None
    self._plural_expr = None