util.py 文件源码

def astimezone(obj):
    """
    Interprets an object as a timezone.

    :rtype: tzinfo

    """
    if isinstance(obj, six.string_types):
        return timezone(obj)
    if isinstance(obj, tzinfo):
        if not hasattr(obj, 'localize') or not hasattr(obj, 'normalize'):
            raise TypeError('Only timezones from the pytz library are supported')
        if obj.zone == 'local':
            raise ValueError(
                'Unable to determine the name of the local timezone -- you must explicitly '
                'specify the name of the local timezone. Please refrain from using timezones like '
                'EST to prevent problems with daylight saving time. Instead, use a locale based '
                'timezone name (such as Europe/Helsinki).')
        return obj
    if obj is not None:
        raise TypeError('Expected tzinfo, got %s instead' % obj.__class__.__name__)