'Set the annotation content.
Parameters
content : str
The content.
content_type : str
Content type. Currently supported are \'text/plain\' \'text/html\'
(subset supported by `QTextDocument`) and `text/rst`.'

def set_content(self, content, content_type='text/plain'):

    if ((self.__content != content) or (self.__content_type != content_type)):
        text_changed = (self.__content != content)
        self.__content = content
        self.__content_type = content_type
        self.content_changed.emit(content, content_type)
        if text_changed:
            self.text_changed.emit(content)
