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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 metadefs_namespace_list(request, filters=None, sort_dir='asc', sort_key='namespace', marker=None, paginate=False):
 """Retrieve a listing of Namespaces :param paginate: If true will perform pagination based on settings. :param marker: Specifies the namespace of the last-seen namespace. The typical pattern of limit and marker is to make an initial limited request and then to use the last namespace from the response as the marker parameter in a subsequent limited request. With paginate, limit is automatically set. :param sort_dir: The sort direction ('asc' or 'desc'). :param sort_key: The field to sort on (for example, 'created_at'). Default is namespace. The way base namespaces are loaded into glance typically at first deployment is done in a single transaction giving them a potentially unpredictable sort result when using create_at. :param filters: specifies addition fields to filter on such as resource_types. :returns A tuple of three values: 1) Current page results 2) A boolean of whether or not there are previous page(s). 3) A boolean of whether or not there are more page(s). """

    # Listing namespaces requires the v2 API. If not supported we return an
    # empty array so callers don't need to worry about version checking.
    if get_version() < 2:
        return [], False, False

    if filters is None:
        filters = {}
    limit = getattr(settings, 'API_RESULT_LIMIT', 1000)
    page_size = utils.get_page_size(request)

    if paginate:
        request_size = page_size + 1
    else:
        request_size = limit

    kwargs = {'filters': filters}
    if marker:
        kwargs['marker'] = marker
    kwargs['sort_dir'] = sort_dir
    kwargs['sort_key'] = sort_key

    namespaces_iter = glanceclient(request, '2').metadefs_namespace.list(
        page_size=request_size, limit=limit, **kwargs)

    # Filter the namespaces based on the provided properties_target since this
    # is not supported by the metadata namespaces API.
    resource_types = filters.get('resource_types')
    properties_target = filters.get('properties_target')
    if resource_types and properties_target:
        namespaces_iter = filter_properties_target(namespaces_iter,
                                                   resource_types,
                                                   properties_target)

    has_prev_data = False
    has_more_data = False
    if paginate:
        namespaces = list(itertools.islice(namespaces_iter, request_size))
        # first and middle page condition
        if len(namespaces) > page_size:
            namespaces.pop(-1)
            has_more_data = True
            # middle page condition
            if marker is not None:
                has_prev_data = True
        # first page condition when reached via prev back
        elif sort_dir == 'desc' and marker is not None:
            has_more_data = True
        # last page condition
        elif marker is not None:
            has_prev_data = True
    else:
        namespaces = list(namespaces_iter)

    namespaces = [Namespace(namespace) for namespace in namespaces]
    return namespaces, has_more_data, has_prev_data