Returns an HTML snippet for a CGI argument.

    Args:
        argument: A string representing an CGI argument name in a form.
        form: A CGI FieldStorage object.

    Returns:
        String HTML representing the CGI value and variable.

def html_for_cgi_argument(argument, form):
    """Returns an HTML snippet for a CGI argument.

    Args:
        argument: A string representing an CGI argument name in a form.
        form: A CGI FieldStorage object.

    Returns:
        String HTML representing the CGI value and variable.
    """
    value = form[argument].value if argument in form else None
    return KEY_VALUE_TEMPLATE.format(argument, value)