How to use the pdfplumber.utils.within_bbox function in pdfplumber

def results(self):
        r = []
        for col in [ "c1", "c2", "c3", "c4" ]:
            b = within_bbox(self.chars, self.bboxes[col])
            r += self.parse_col(b)
        return r

def ballots_cast(self):
        h2_chars = within_bbox(self.chars, self.bboxes["h2"])
        txt = h2_chars.groupby("top").apply(collate_chars).iloc[0]
        return int(re.match(r"(\d+) BALLOTS CAST", txt).group(1))

if x in (None, ""): return None
            return int(x.replace(",", ""))

        def parse_row(row):
            return dict((COLUMNS[i], parse_value(i, v))
                for i, v in enumerate(row))

        parsed_table = [ parse_row(row) for row in table ]

        # [1:] because first column is state name
        for c in COLUMNS[1:]:
            total = parsed_table[-1][c]
            colsum = sum(row[c] or 0 for row in parsed_table)
            assert(colsum == (total * 2))

        month_chars = within_bbox(page.chars, (0, 35, self.PDF_WIDTH, 65))
        month_text = collate_chars(month_chars)
        assert(month_text == "November - 2015")

table = pd.DataFrame(table)

        def parse_value(x):
            if pd.isnull(x) or x == "": return None
            return int(x.replace(",", ""))

        table.columns = COLUMNS
        table[table.columns[1:]] = table[table.columns[1:]].applymap(parse_value)

        # [1:] because first column is state name
        for c in COLUMNS[1:]:
            total = table[c].iloc[-1]
            colsum = table[c].sum()
            assert(colsum == (total * 2))

        month_chars = within_bbox(page.chars, (0, 35, self.PDF_WIDTH, 65))
        month_text = collate_chars(month_chars)
        assert(month_text == "November - 2015")

def registered_voters(self):
        h2_chars = within_bbox(self.chars, self.bboxes["h2"])
        txt = h2_chars.groupby("top").apply(collate_chars).iloc[1]
        return int(re.match(r"(\d+) REGISTERED VOTERS", txt).group(1))

def objects(self):
                if hasattr(self, "_objects"): return self._objects
                self._objects = utils.within_bbox(
                    self.parent_page.objects,
                    self.bbox)
                return self._objects