common.py 文件源码

def validate_positive_float(option, value):
    """Validates that 'value' is a float, or can be converted to one, and is
       positive.
    """
    err = ConfigurationError("%s must be a positive int or float" % (option,))
    try:
        value = float(value)
    except (ValueError, TypeError):
        raise err

    # float('inf') doesn't work in 2.4 or 2.5 on Windows, so just cap floats at
    # one billion - this is a reasonable approximation for infinity
    if not 0 < value < 1e9:
        raise err

    return value