def subst_variables_in_str(line: str, values: dict, start_char: str = "%") -> object:
    """
    Replace variables inside the specified string

    :param line:        String to replace the variables in.
    :param values:      Dictionary, holding variables and their values.
    :param start_char:  Character used to identify the beginning of a variable inside the string.
    :return:            String where variables have been replaced by their respective values.
    """
    ret_val = line

    for k, v in zip(values.keys(), values.values()):
        ret_val = ret_val.replace(start_char + str(k), str(v))

    return ret_val