Get the real value from a comma-separated header based on the
        configured number of trusted proxies.

        :param trusted: Number of values to trust in the header.
        :param value: Header value to parse.
        :return: The real value, or ``None`` if there are fewer values
            than the number of trusted proxies.

        .. versionadded:: 0.15

def _get_trusted_comma(self, trusted, value):
        """Get the real value from a comma-separated header based on the
        configured number of trusted proxies.

        :param trusted: Number of values to trust in the header.
        :param value: Header value to parse.
        :return: The real value, or ``None`` if there are fewer values
            than the number of trusted proxies.

        .. versionadded:: 0.15
        """
        if not (trusted and value):
            return
        values = [x.strip() for x in value.split(",")]
        if len(values) >= trusted:
            return values[-trusted]