How to use the curtsies.formatstring.Chunk function in curtsies

def test_reusing_same_splitter(self):
        c = Chunk('asdf', {'fg': 32})
        s1 = c.splitter()
        self.assertEqual(s1.request(3), (3, Chunk('asd', {'fg': 32})))
        s1.reinit(c)
        self.assertEqual(s1.request(3), (3, Chunk('asd', {'fg': 32})))
        s1.reinit(c)
        self.assertEqual(s1.request(3), (3, Chunk('asd', {'fg': 32})))

        c2 = Chunk('abcdef', {})
        s1.reinit(c2)
        self.assertEqual(s1.request(3), (3, Chunk('abc')))

def test_width_awareness(self):
        s = Chunk('asdf')
        self.assertEqual(Chunk('ab\u0300c').splitter().request(3), (3, Chunk('ab\u0300c')))
        self.assertEqual(Chunk('ab\u0300c').splitter().request(2), (2, Chunk('ab\u0300')))

        s = Chunk('ab\u0300c').splitter()
        self.assertEqual(s.request(1), (1, Chunk('a')))
        self.assertEqual(s.request(2), (2, Chunk('b\u0300c')))

        c = Chunk('aＥbc')
        self.assertEqual(c.splitter().request(4), (4, Chunk('aＥb')))
        s = c.splitter()
        self.assertEqual(s.request(2), (2, Chunk('a ')))
        self.assertEqual(s.request(2), (2, Chunk('Ｅ')))
        self.assertEqual(s.request(2), (2, Chunk('bc')))
        self.assertEqual(s.request(2), None)

def test_width_awareness(self):
        s = Chunk('asdf')
        self.assertEqual(Chunk('ab\u0300c').splitter().request(3), (3, Chunk('ab\u0300c')))
        self.assertEqual(Chunk('ab\u0300c').splitter().request(2), (2, Chunk('ab\u0300')))

        s = Chunk('ab\u0300c').splitter()
        self.assertEqual(s.request(1), (1, Chunk('a')))
        self.assertEqual(s.request(2), (2, Chunk('b\u0300c')))

        c = Chunk('aＥbc')
        self.assertEqual(c.splitter().request(4), (4, Chunk('aＥb')))
        s = c.splitter()
        self.assertEqual(s.request(2), (2, Chunk('a ')))
        self.assertEqual(s.request(2), (2, Chunk('Ｅ')))
        self.assertEqual(s.request(2), (2, Chunk('bc')))
        self.assertEqual(s.request(2), None)

def test_width_awareness(self):
        s = Chunk('asdf')
        self.assertEqual(Chunk('ab\u0300c').splitter().request(3), (3, Chunk('ab\u0300c')))
        self.assertEqual(Chunk('ab\u0300c').splitter().request(2), (2, Chunk('ab\u0300')))

        s = Chunk('ab\u0300c').splitter()
        self.assertEqual(s.request(1), (1, Chunk('a')))
        self.assertEqual(s.request(2), (2, Chunk('b\u0300c')))

        c = Chunk('aＥbc')
        self.assertEqual(c.splitter().request(4), (4, Chunk('aＥb')))
        s = c.splitter()
        self.assertEqual(s.request(2), (2, Chunk('a ')))
        self.assertEqual(s.request(2), (2, Chunk('Ｅ')))
        self.assertEqual(s.request(2), (2, Chunk('bc')))
        self.assertEqual(s.request(2), None)

def test_width_awareness(self):
        s = Chunk('asdf')
        self.assertEqual(Chunk('ab\u0300c').splitter().request(3), (3, Chunk('ab\u0300c')))
        self.assertEqual(Chunk('ab\u0300c').splitter().request(2), (2, Chunk('ab\u0300')))

        s = Chunk('ab\u0300c').splitter()
        self.assertEqual(s.request(1), (1, Chunk('a')))
        self.assertEqual(s.request(2), (2, Chunk('b\u0300c')))

        c = Chunk('aＥbc')
        self.assertEqual(c.splitter().request(4), (4, Chunk('aＥb')))
        s = c.splitter()
        self.assertEqual(s.request(2), (2, Chunk('a ')))
        self.assertEqual(s.request(2), (2, Chunk('Ｅ')))
        self.assertEqual(s.request(2), (2, Chunk('bc')))
        self.assertEqual(s.request(2), None)

def test_chunk_splitter(self):
        splitter = Chunk('asdf', {'fg': 32}).splitter()
        self.assertEqual(splitter.request(1), (1, Chunk('a', {'fg': 32})))
        self.assertEqual(splitter.request(4), (3, Chunk('sdf', {'fg': 32})))
        self.assertEqual(splitter.request(4), None)

def test_width_awareness(self):
        s = Chunk('asdf')
        self.assertEqual(Chunk('ab\u0300c').splitter().request(3), (3, Chunk('ab\u0300c')))
        self.assertEqual(Chunk('ab\u0300c').splitter().request(2), (2, Chunk('ab\u0300')))

        s = Chunk('ab\u0300c').splitter()
        self.assertEqual(s.request(1), (1, Chunk('a')))
        self.assertEqual(s.request(2), (2, Chunk('b\u0300c')))

        c = Chunk('aＥbc')
        self.assertEqual(c.splitter().request(4), (4, Chunk('aＥb')))
        s = c.splitter()
        self.assertEqual(s.request(2), (2, Chunk('a ')))
        self.assertEqual(s.request(2), (2, Chunk('Ｅ')))
        self.assertEqual(s.request(2), (2, Chunk('bc')))
        self.assertEqual(s.request(2), None)

else:
                chunks = []
                cur_fmt = {}
                for x in tokens_and_strings:
                    if isinstance(x, dict):
                        cur_fmt.update(x)
                    elif isinstance(x, (bytes, unicode)):
                        atts = parse_args('', dict((k, v)
                                          for k, v in cur_fmt.items()
                                          if v is not None))
                        chunks.append(Chunk(x, atts=atts))
                    else:
                        raise Exception("logic error")
                return FmtStr(*chunks)
        else:
            return FmtStr(Chunk(s))

inserted = True

            elif bfs_start <= start < bfs_end:
                divide = start - bfs_start
                head = Chunk(bfs.s[:divide], atts=bfs.atts)
                tail = Chunk(bfs.s[end - bfs_start:], atts=bfs.atts)
                new_components.extend([head] + new_fs.chunks)
                inserted = True

                if bfs_start < end < bfs_end:
                    tail = Chunk(bfs.s[end - bfs_start:], atts=bfs.atts)
                    new_components.append(tail)

            elif bfs_start < end < bfs_end:
                divide = start - bfs_start
                tail = Chunk(bfs.s[end - bfs_start:], atts=bfs.atts)
                new_components.append(tail)

            elif bfs_start >= end or bfs_end <= start:
                new_components.append(bfs)

        if not inserted:
            new_components.extend(new_fs.chunks)
            inserted = True

        return FmtStr(*[s for s in new_components if s.s])

def __getitem__(self, index):
        index = normalize_slice(len(self), index)
        counter = 0
        parts = []
        for chunk in self.chunks:
            if index.start < counter + len(chunk) and index.stop > counter:
                start = max(0, index.start - counter)
                end = min(index.stop - counter, len(chunk))
                if end - start == len(chunk):
                    parts.append(chunk)
                else:
                    s_part = chunk.s[max(0, index.start - counter): index.stop - counter]
                    parts.append(Chunk(s_part, chunk.atts))
            counter += len(chunk)
            if index.stop < counter:
                break
        return FmtStr(*parts) if parts else fmtstr('')