def inject_content(self, content, inject_string):
        """
        Inject inject_string into a text buffer, wrapped with
        #{{ wrapper }} comments if condition lambda is not
        satisfied or is None. Remove old instances of injects if they
        exist.
        """
        inject_string = _unicode(inject_string)
        content = self.wrapper_match.sub("", _unicode(content))
        if self.override_match:
            sprinter_overrides = self.override_match.search(content)
            if sprinter_overrides:
                content = self.override_match.sub("", content)
                sprinter_overrides = sprinter_overrides.groups()[0]
            else:
                sprinter_overrides = ""
        content += """
%s
%s
%s
""" % (self.wrapper, inject_string.rstrip(), self.wrapper)
        if self.override_match:
            content += sprinter_overrides.rstrip() + "\n"
        return content