def parse_lowercase_headers(headers):
    """makes the headers lower case
    :param HTTPMessage headers:
    :return dict:
    """
    response_headers = {}
    for header_pair in headers.items():
        name = header_pair[0].lower()
        value = header_pair[1]
        if name == 'set-cookie' and name in response_headers:
            response_headers[name] = '{};{}'.format(response_headers[name],
                value)
        else:
            response_headers[name] = value
    return response_headers
