def parse_headers(req_headers):
    """
    Load headers from request to dictionary

    Args:
        req_headers (dict): the request's headers

    Returns:
        dict: dictionary hosting the request headers
    """
    headers_lst = ["CONTENT-TYPE", "CONTENT-ENCODING", "RESPONSE-FORMAT",
                   "CLEAN", "DISPLAY-POST-PREPROCCES",
                   "DISPLAY-TOKENS", "DISPLAY-TOKEN-TEXT", "IS-HTML"]
    headers = {}
    for header_tag in headers_lst:
        if header_tag in req_headers:
            headers[header_tag] = req_headers[header_tag]
        else:
            headers[header_tag] = None
    return headers