def read_forcefully(line, default=''):
    if default != '':
        line = line + ' (default is "' + default + '", to accept just hit return)'
    value = input(line + ': ').strip()
    if value == '':
        if default == '':
            print('- This information is obligatory!')
            return read_forcefully(line)
        else:
            print('- Using the default value, "' + default + '"')
            return default
    else:
        return value