def compile(self, code):
        """
        Compile a simex code (e.g. <a href="{{ url }}">{{ anything }}</a>) to regex.

        Returns regex.
        """
        is_plain_text = True
        compiled_regex = r""
        for chunk in self.delimiter_regex().split(code):
            if is_plain_text:
                compiled_regex = compiled_regex + simex_escape(chunk, flexible_whitespace=self._flexible_whitespace)
            else:
                stripped_chunk = chunk.strip()
                if stripped_chunk in self._regexes.keys():
                    compiled_regex = u"{0}{1}".format(
                        compiled_regex,
                        self._regexes[stripped_chunk]
                    )
                else:
                    raise KeyNotFound("'{0}' not found in keys")
            is_plain_text = not is_plain_text
        if self._exact:
            compiled_regex = r"^" + compiled_regex + r"$"
        return compile(compiled_regex)