You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: dnn_face_detector.m
    path of file: ./repos/mexopencv/samples
    
    the code of the file until where you have to start completion: %% DNN: Face Detection
% Face detector based on SSD framework (Single Shot MultiBox Detector),
% using a reduced ResNet-10 model.
%
% Sources:
%
% * <https://github.com/opencv/opencv/blob/3.4.1/samples/dnn/resnet_ssd_face_python.py>
% * <https://githu
    
function dname = get_dnn_dir(dname)
    %GET_DNN_DIR  Path to model files, and show where to get them if missing

    dname = fullfile(mexopencv.root(), 'test', 'dnn', dname);
    b = isdir(dname);
    if ~b
        % display help of calling function
        % (assumed to be a local function in current file)
        st = dbstack(1);
        help([mfilename() filemarker() st(1).name])
    end