def taputil_find_header(headers, key):
    """Searches for the specified keyword

    Parameters
    ----------
    headers : HTTP(s) headers object, mandatory
        HTTP(s) response headers
    key : str, mandatory
        header key to be searched for

    Returns
    -------
    The requested header value or None if the header is not found
    """
    for entry in headers:
        if key.lower() == entry[0].lower():
            return entry[1]
    return None