def key_value_to_str_if_not_none(key, value, separator=' ', suffix='\n'):
    """
    Helper method that, given a key, value, separator and suffix, it will return the string
    '<key><separator><value><suffix>' if value is not None, otherwise it will return the empty string ''
    :param key: key
    :param value: value
    :param separator: character to use as separator, default ' '
    :param suffix: character to use as suffix, default '\n'
    :return: '<key><separator><value><suffix>' if value not None, '' otherwise
    """
    if value:
        return "{}{}{}{}".format(key, separator, value, suffix)
    return ""