How to use the bs4.element.SoupStrainer function in bs4

def test_soupstrainer(self):
        """Parsers should be able to work with SoupStrainers."""
        strainer = SoupStrainer("b")
        soup = self.soup("A <b>bold</b>  <i>statement</i>",
                         parse_only=strainer)
        self.assertEqual(soup.decode(), "<b>bold</b>")

def test_soupstrainer(self):
        """Parsers should be able to work with SoupStrainers."""
        strainer = SoupStrainer("b")
        soup = self.soup("A <b>bold</b>  <i>statement</i>",
                         parse_only=strainer)
        self.assertEqual(soup.decode(), "<b>bold</b>")

def test_soupstrainer(self):
        """Parsers should be able to work with SoupStrainers."""
        strainer = SoupStrainer("b")
        soup = self.soup("A <b>bold</b>  <i>statement</i>",
                         parse_only=strainer)
        self.assertEqual(soup.decode(), "<b>bold</b>")

def _find_all(self, name, attrs, text, limit, generator, **kwargs):
        "Iterates over a generator looking for things that match."

        if isinstance(name, SoupStrainer):
            strainer = name
        elif text is None and not limit and not attrs and not kwargs:
            # Optimization to find all tags.
            if name is True or name is None:
                return [element for element in generator
                        if isinstance(element, Tag)]
            # Optimization to find all tags with a given name.
            elif isinstance(name, basestring):
                return [element for element in generator
                        if isinstance(element, Tag) and element.name == name]
            else:
                strainer = SoupStrainer(name, attrs, text, **kwargs)
        else:
            # Build a SoupStrainer
            strainer = SoupStrainer(name, attrs, text, **kwargs)
        results = ResultSet(strainer)
        while True:
            try:
                i = next(generator)
            except StopIteration:
                break
            if i:
                found = strainer.search(i)
                if found:
                    results.append(found)
                    if limit and len(results) >= limit:
                        break
        return results

def _find_all(self, name, attrs, text, limit, generator, **kwargs):
        "Iterates over a generator looking for things that match."

        if text is None and 'string' in kwargs:
            text = kwargs['string']
            del kwargs['string']

        if isinstance(name, SoupStrainer):
            strainer = name
        else:
            strainer = SoupStrainer(name, attrs, text, **kwargs)

        if text is None and not limit and not attrs and not kwargs:
            if name is True or name is None:
                # Optimization to find all tags.
                result = (element for element in generator
                          if isinstance(element, Tag))
                return ResultSet(strainer, result)
            elif isinstance(name, str):
                # Optimization to find all tags with a given name.
                result = (element for element in generator
                          if isinstance(element, Tag)
                            and element.name == name)
                return ResultSet(strainer, result)
        results = ResultSet(strainer)
        while True:
            try: