How to use the mlxtend.file_io.find_files function in mlxtend

def test_ignore_substring():
    path = os.path.join(os.getcwd(),'tests','tests_file_io')
    assert(find_files(substring='test_find_files', path=path, ignore_substring='test_find') == [])

def test_find_files():
    path = os.path.join(os.getcwd(),'tests','tests_file_io')
    expect = [os.path.join(os.getcwd(),'tests','tests_file_io', 'test_find_files.py')]

    assert(find_files(substring='test_find_files', path=path) == expect)
    
    # find recursive
    assert(find_files(substring='test_find_files.py', path=os.getcwd(), recursive=True) == expect)
    
    # find files and check extension
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.py') == expect)
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.txt') == [])

def test_find_files():
    path = os.path.join(os.getcwd(),'tests','tests_file_io')
    expect = [os.path.join(os.getcwd(),'tests','tests_file_io', 'test_find_files.py')]

    assert(find_files(substring='test_find_files', path=path) == expect)
    
    # find recursive
    assert(find_files(substring='test_find_files.py', path=os.getcwd(), recursive=True) == expect)
    
    # find files and check extension
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.py') == expect)
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.txt') == [])

def test_find_files():
    path = os.path.join(os.getcwd(),'tests','tests_file_io')
    expect = [os.path.join(os.getcwd(),'tests','tests_file_io', 'test_find_files.py')]

    assert(find_files(substring='test_find_files', path=path) == expect)
    
    # find recursive
    assert(find_files(substring='test_find_files.py', path=os.getcwd(), recursive=True) == expect)
    
    # find files and check extension
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.py') == expect)
    assert(find_files(substring='test_find_files.py', path=path, check_ext='.txt') == [])

"""
    n = len(paths)

    # must have same number of paths and extensions
    assert(len(paths) >= 2)
    if extensions:
        assert(len(extensions) == n)
    else:
        extensions = ['' for i in range(n)]

    base = find_files(path=paths[0],
                      substring=substring,
                      check_ext=extensions[0],
                      ignore_invisible=ignore_invisible,
                      ignore_substring=ignore_substring)
    rest = [find_files(path=paths[i],
                       substring=substring,
                       check_ext=extensions[i],
                       ignore_invisible=ignore_invisible,
                       ignore_substring=ignore_substring) for i in range(1, n)]

    groups = {}
    for f in base:
        basename = os.path.splitext(os.path.basename(f))[0]
        basename = re.sub('\%s$' % rstrip, '', basename)
        groups[basename] = [f]

    # groups = {os.path.splitext(os.path.basename(f))[0].rstrip(rstrip):[f]
    #           for f in base}

    for idx, r in enumerate(rest):
        for f in r:

Examples
    -----------
    For usage examples, please see
    http://rasbt.github.io/mlxtend/user_guide/file_io/find_filegroups/

    """
    n = len(paths)

    # must have same number of paths and extensions
    assert(len(paths) >= 2)
    if extensions:
        assert(len(extensions) == n)
    else:
        extensions = ['' for i in range(n)]

    base = find_files(path=paths[0],
                      substring=substring,
                      check_ext=extensions[0],
                      ignore_invisible=ignore_invisible,
                      ignore_substring=ignore_substring)
    rest = [find_files(path=paths[i],
                       substring=substring,
                       check_ext=extensions[i],
                       ignore_invisible=ignore_invisible,
                       ignore_substring=ignore_substring) for i in range(1, n)]

    groups = {}
    for f in base:
        basename = os.path.splitext(os.path.basename(f))[0]
        basename = re.sub('\%s$' % rstrip, '', basename)
        groups[basename] = [f]