How to use the cssutils.parseString function in cssutils

items = sorted(stylizer.page_rule.items())
            css = ';\n'.join("%s: %s" % (key, val) for key, val in items)
            css = ('@page {\n%s\n}\n'%css) if items else ''
            rules = [r.cssText for r in stylizer.font_face_rules +
                    self.embed_font_rules]
            raw = '\n\n'.join(rules)
            css += '\n\n' + raw
            global_css[css].append(item)

        gc_map = {}
        manifest = self.oeb.manifest
        for css in global_css:
            href = None
            if css.strip():
                id_, href = manifest.generate('page_css', 'page_styles.css')
                manifest.add(id_, href, CSS_MIME, data=cssutils.parseString(css,
                    validate=False))
            gc_map[css] = href

        ans = {}
        for css, items in global_css.iteritems():
            for item in items:
                ans[item] = gc_map[css]
        return ans

def loads(css, verbose=VERBOSE):
    sheet = cssutils.parseString(css, validate=verbose)
    return Element(sheet, verbose=verbose)

"""
        This function will cache the result from cssutils
        It is a big gain when number of rules is big
        Maximum cache entries are 1000. This is mainly for
        protecting memory leak in case something gone wild.
        Be aware that you can turn the cache off in Premailer

        Args:
            css_body(str): css rules in string format
            validate(bool): if cssutils should validate

        Returns:
            cssutils.css.cssstylesheet.CSSStyleSheet

    """
    return cssutils.parseString(css_body, validate=validate)

def adddata(self):
        """Add more data to the svgimgutils"""
        self.style_element = self.root.find('./' + self.root[0].tag + '/' + self.root[0][0].tag)
        self.number_of_classes = cssutils.parseString(self.style_element.text).cssRules.length

def get_css_style(csstext, style):
    cssstyle = ""
    if csstext:
        try:
            import cssutils
            from cssutils import parseString
            cssutils.log.setLevel(logging.CRITICAL)
        except ImportError:
            return ""
        cssnode = parseString(csstext)
        stylesheet = cssnode.cssRules
        for rule in stylesheet:
            if rule.selectorText.replace(".", "") == style:
                cssstyle = str(rule.style.cssText)
    return cssstyle

def getMaskedClasses(self, soup):

		masked_classes = []

		mask_style = soup.find_all("style", text=re.compile(r"\.chp\-release\..*?display:none"))
		for style in mask_style:
			parsed_style = cssutils.parseString(style.get_text())
			for rule in parsed_style:
				if rule.type == rule.STYLE_RULE:
					disp = rule.style.getProperty('display')
					if disp and disp.cssValue.cssText.lower() == "none":
						for selector in rule.selectorList:
							if len(selector.seq) == 2:
								root, key = selector.seq
								if root.value == ".chp-release" and root.type == 'class':
									masked_classes.append(key.value[1:])

		print("Masked classes:")
		print(masked_classes)

		return masked_classes

def format_body(self, body):
        sheet = cssutils.parseString(body)
        return sheet.cssText

def _minified():
			href = self.base_url if self.base_url != '' else None
			sheet = cssutils.parseString(css, href=href)
			sheet = cssutils.resolveImports(sheet)
			cssutils.ser.prefs.useMinified()
			return sheet.cssText
		return self.cached(css.encode('utf-8'), _minified)

def replace_css(self, css):
        manifest = self.oeb.manifest
        for item in manifest.values():
            if item.media_type in OEB_STYLES:
                manifest.remove(item)
        id, href = manifest.generate('css', 'stylesheet.css')
        item = manifest.add(id, href, CSS_MIME, data=cssutils.parseString(css,
            validate=False))
        self.oeb.manifest.main_stylesheet = item
        return href

"""
        This function will cache the result from cssutils
        It is a big gain when number of rules is big
        Maximum cache entries are 1000. This is mainly for
        protecting memory leak in case something gone wild.
        Be aware that you can turn the cache off in Premailer

        Args:
            css_body(str): css rules in string format
            validate(bool): if cssutils should validate

        Returns:
            cssutils.css.cssstylesheet.CSSStyleSheet

    """
    return cssutils.parseString(css_body, validate=validate)