How to use the creoleparser.elements.BlockElement function in Creoleparser

class HTMLEntity(creoleparser.elements.InlineElement):
    # Allows HTML elements to be passed through
    def __init__(self):
        super(HTMLEntity, self).__init__('span', ['&', ';'])
        self.regexp = re.compile(self.re_string())

    def re_string(self):
        return '&([A-Za-z]\w{1,24}|#\d{2,7}|#[Xx][0-9a-zA-Z]{2,6});'

    def _build(self, mo, element_store, environ):
        content = mo.group(1)
        return creoleparser.core.bldr.tag.__getattr__('span')(Markup('&' + content + ';'))


class CodeBlock(creoleparser.elements.BlockElement):
    """
    A block of code that gets syntax-highlited
    """

    def __init__(self):
        super(CodeBlock, self).__init__('pre', ['{{{', '}}}'])
        self.regexp = re.compile(self.re_string(), re.DOTALL + re.MULTILINE)
        self.regexp2 = re.compile(self.re_string2(), re.MULTILINE)

    def re_string(self):
        start = '^\{\{\{\s*\[(' + brushre + ')\]\s*\n'
        content = r'(.+?\n)'
        end = r'\}\}\}\s*?$'
        return start + content + end

    def re_string2(self):

class HTMLEntity(creoleparser.elements.InlineElement):
    # Allows HTML elements to be passed through
    def __init__(self):
        super(HTMLEntity, self).__init__('span', ['&',';'])
        self.regexp = re.compile(self.re_string())

    def re_string(self):
        return '&([A-Za-z]\w{1,24}|#\d{2,7}|#[Xx][0-9a-zA-Z]{2,6});'

    def _build(self,mo,element_store, environ):
        content = mo.group(1)
        return creoleparser.core.bldr.tag.__getattr__('span')(Markup('&' + content + ';'))


class CodeBlock(creoleparser.elements.BlockElement):
    """
    A block of code that gets syntax-highlited
    """
    def __init__(self):
        super(CodeBlock,self).__init__('pre', ['{{{','}}}'])
        self.regexp = re.compile(self.re_string(), re.DOTALL+re.MULTILINE)
        self.regexp2 = re.compile(self.re_string2(), re.MULTILINE)

    def re_string(self):
        start = '^\{\{\{\s*\[(' + brushre + ')\]\s*\n'
        content = r'(.+?\n)'
        end = r'\}\}\}\s*?$'
        return start + content + end

    def re_string2(self):
        """Finds a closing token with a space at the start of the line."""