How to use the sigal.image.get_exif_tags function in sigal

def test_get_exif_tags():
    test_image = '11.jpg'
    src_file = os.path.join(CURRENT_DIR, 'sample', 'pictures', 'dir1', 'test1',
                            test_image)
    data = get_exif_data(src_file)
    simple = get_exif_tags(data, datetime_format='%d/%m/%Y')
    assert simple['fstop'] == 3.9
    assert simple['focal'] == 12.0
    assert simple['iso'] == 50
    assert simple['Make'] == 'NIKON'
    assert simple['datetime'] == '22/01/2006'
    if PIL.PILLOW_VERSION == '3.0.0':
        assert simple['exposure'] == 0.00100603
    else:
        assert simple['exposure'] == '100603/100000000'

    data = {'FNumber': [1, 0], 'FocalLength': [1, 0], 'ExposureTime': 10}
    simple = get_exif_tags(data)
    assert 'fstop' not in simple
    assert 'focal' not in simple
    assert simple['exposure'] == '10'

def test_iso_speed_ratings():
    data = {'ISOSpeedRatings': ()}
    simple = get_exif_tags(data)
    assert 'iso' not in simple

    data = {'ISOSpeedRatings': None}
    simple = get_exif_tags(data)
    assert 'iso' not in simple

    data = {'ISOSpeedRatings': 125}
    simple = get_exif_tags(data)
    assert 'iso' in simple

def test_exif_copy(tmpdir):
    "Test if EXIF data can transferred copied to the resized image."

    test_image = '11.jpg'
    src_file = os.path.join(CURRENT_DIR, 'sample', 'pictures', 'dir1', 'test1',
                            test_image)
    dst_file = str(tmpdir.join(test_image))

    settings = create_settings(img_size=(300, 400), copy_exif_data=True)
    generate_image(src_file, dst_file, settings)
    simple = get_exif_tags(get_exif_data(dst_file))
    assert simple['iso'] == 50

    settings['copy_exif_data'] = False
    generate_image(src_file, dst_file, settings)
    simple = get_exif_tags(get_exif_data(dst_file))
    assert not simple

src_file = os.path.join(CURRENT_DIR, 'sample', 'pictures', 'dir1', 'test1',
                            test_image)
    data = get_exif_data(src_file)
    simple = get_exif_tags(data, datetime_format='%d/%m/%Y')
    assert simple['fstop'] == 3.9
    assert simple['focal'] == 12.0
    assert simple['iso'] == 50
    assert simple['Make'] == 'NIKON'
    assert simple['datetime'] == '22/01/2006'
    if PIL.PILLOW_VERSION == '3.0.0':
        assert simple['exposure'] == 0.00100603
    else:
        assert simple['exposure'] == '100603/100000000'

    data = {'FNumber': [1, 0], 'FocalLength': [1, 0], 'ExposureTime': 10}
    simple = get_exif_tags(data)
    assert 'fstop' not in simple
    assert 'focal' not in simple
    assert simple['exposure'] == '10'

    data = {'ExposureTime': '--', 'DateTimeOriginal': '---',
            'GPSInfo': {'GPSLatitude': ((34, 0), (1, 0), (4500, 100)),
                        'GPSLatitudeRef': 'N',
                        'GPSLongitude': ((116, 0), (8, 0), (3900, 100)),
                        'GPSLongitudeRef': 'W'}}
    simple = get_exif_tags(data)
    assert 'exposure' not in simple
    assert 'datetime' not in simple
    assert 'gps' not in simple

def test_exif_gps(tmpdir):
    """Test reading out correct geo tags"""

    test_image = 'flickr_jerquiaga_2394751088_cc-by-nc.jpg'
    src_file = os.path.join(CURRENT_DIR, 'sample', 'pictures', 'dir1', 'test1',
                            test_image)
    dst_file = str(tmpdir.join(test_image))

    settings = create_settings(img_size=(400, 300), copy_exif_data=True)
    generate_image(src_file, dst_file, settings)
    simple = get_exif_tags(get_exif_data(dst_file))
    assert 'gps' in simple

    lat = 34.029167
    lon = -116.144167

    assert abs(simple['gps']['lat'] - lat) < 0.0001
    assert abs(simple['gps']['lon'] - lon) < 0.0001

def test_null_exposure_time():
    data = {'ExposureTime': (0, 0)}
    simple = get_exif_tags(data)
    assert 'exposure' not in simple

def exif(self):
        datetime_format = self.settings['datetime_format']
        return (get_exif_tags(self.raw_exif, datetime_format=datetime_format)
                if self.raw_exif and self.ext in ('.jpg', '.jpeg') else None)