How to use the pysubs2.SSAFile function in pysubs2

def test_repr_default():
    subs = SSAFile()
    ref = ""
    assert repr(subs) == ref

def test_simple_write():
    subs = SSAFile()

    e1 = SSAEvent()
    e1.start = 0
    e1.end = 60000
    e1.text = "An example subtitle."

    e2 = SSAEvent()
    e2.start = 60000
    e2.end = 120000
    e2.text = "Subtitle number\\Ntwo."

    e3 = SSAEvent()
    e3.start = 60000
    e3.end = 120000
    e3.text = "Invisible subtitle."
    e3.is_comment = True

def build_ref():
    subs = SSAFile()
    subs.info["My Custom Info"] = "Some: Test, String."
    subs.styles["left"] = SSAStyle(alignment=7, bold=True)
    subs.styles["topleft"] = SSAStyle(alignment=4)
    subs.append(SSAEvent(start=0, end=make_time(m=1), text="An, example, subtitle."))
    subs.append(SSAEvent(start=0, end=make_time(m=1), type="Comment", text="You can't see this one."))
    subs.append(SSAEvent(start=make_time(m=1), end=make_time(m=2), text="Subtitle number\\Ntwo."))
    return subs

def build(self, **extra):
        from pysubs2 import SSAFile, SSAEvent, Color # type: ignore[import]
        millis = lambda td: td / timedelta(milliseconds=1)
        subs = (
            SSAEvent(
                start=millis(t - self.start),
                end  =millis(t - self.start + timedelta(seconds=length)),
                text=text.replace('\n', r'\N'), # \N necessary for SSA files
            ) for t, text, length in self.l
        )
        sf = SSAFile()
        style = sf.styles['Default'].copy()
        style.fontsize = 16 # default is 20, bit too much??
        style.outlinecolor = Color(0, 0, 0, 50) # semitransparent
        style.shadow = 0.0

        style.outline = 0.1
        style.borderstyle = 3 # no idea why 3, but it makes the background apperar in conjunction with outline

        for k, v in extra.items():
            setattr(style, k, v)
        sf.styles['Default'] = style
        for s in subs:
            sf.append(s)
        return sf.to_string('ass')

def test_import_styles():
    red1 = SSAStyle()
    red2 = SSAStyle()
    green = SSAStyle()
    subs1 = SSAFile()
    subs2 = SSAFile()

    def prepare():
        subs1.styles = {}
        subs2.styles = {}
        subs1.styles["green"] = green
        subs1.styles["red"] = red1
        subs2.styles["red"] = red2

    prepare()
    subs2.import_styles(subs1)
    assert subs2.styles["green"] is green
    assert subs2.styles["red"] is red1

    prepare()
    subs2.import_styles(subs1, overwrite=False)

def test_read_position_styling():
    """position is ignored, italic is converted, color is ignored"""

    text = dedent("""\
    1
    00:00:10,500 --> 00:00:13,000  X1:63 X2:223 Y1:43 Y2:58
    <i>Elephant's Dream</i>

    2
    00:00:15,000 --&gt; 00:00:18,000  X1:53 X2:303 Y1:438 Y2:453
    <font color="cyan">At the left we can see...</font>
    """)

    ref = SSAFile()
    ref.append(SSAEvent(start=make_time(s=10.5), end=make_time(s=13), text="{\\i1}Elephant's Dream{\\i0}"))
    ref.append(SSAEvent(start=make_time(s=15), end=make_time(s=18), text="At the left we can see..."))

    subs = SSAFile.from_string(text)
    assert subs.equals(ref)

assert subs1[0] == SSAEvent(start=make_time(ms=12300), end=make_time(ms=45600), text="Line 1")

    test_input2 = "[123][456] / Line 1|   Line 2/2"
    subs2 = SSAFile.from_string(test_input2)
    assert len(subs2) == 1
    assert subs2[0] == SSAEvent(start=make_time(ms=12300), end=make_time(ms=45600), text="{\i1}Line 1{\i0}\\NLine2/2")

    test_input3 = dedent("""
    [123][456] Line 1
    [321][456] / Line 2|   Line 3
    (123)(456)This line should not be parsed
    This line should also not be parsed
    
    [789][1234] /Line 4""")

    subs3 = SSAFile.from_string(test_input3)
    assert len(subs3) == 3
    assert subs3[0] == SSAEvent(start=make_time(ms=12300), end=make_time(ms=45600), text="Line 1")
    assert subs3[1] == SSAEvent(start=make_time(ms=32100), end=make_time(ms=45600), text="{\i1}Line 2{\i0}\\NLine 3")
    assert subs3[2] == SSAEvent(start=make_time(ms=78900), end=make_time(ms=123400), text="{\i1}Line 4{\i0}")

def test_read_bad_tags():
    """missing opening/closing tag, bad nesting, extra whitespace"""

    text = dedent("""\
    1
    00:00:10,500 --> 00:00:13,000
    &lt; u&gt;<i><font color="red">Elephant's &lt; s&gt;Dream&lt; /  i &gt; Is Long And Badly Nested

    """)

    ref = SSAFile()
    ref.append(SSAEvent(start=make_time(s=10.5), end=make_time(s=13), text="{\\u1}{\\i1}Elephant's {\\s1}Dream{\\i0} Is Long{\\s0} And Badly Nested"))

    subs = SSAFile.from_string(text)
    assert subs.equals(ref)
</font></i>