def value_to_wep(confidence_value):
    """
    This method will transform an integer value into the WEP scale string
    representation.

    The scale for this confidence representation is the following:

    .. list-table:: STIX Confidence to WEP
        :header-rows: 1

        * - Range of Values
          - WEP
        * - 0
          - Impossible
        * - 1-19
          - Highly Unlikely/Almost Certainly Not
        * - 20-39
          - Unlikely/Probably Not
        * - 40-59
          - Even Chance
        * - 60-79
          - Likely/Probable
        * - 80-99
          - Highly likely/Almost Certain
        * - 100
          - Certain

    Args:
        confidence_value (int): An integer value between 0 and 100.

    Returns:
        str: A string corresponding to the WEP scale.

    Raises:
        ValueError: If `confidence_value` is out of bounds.

    """
    if confidence_value == 0:
        return 'Impossible'
    elif 19 >= confidence_value >= 1:
        return 'Highly Unlikely/Almost Certainly Not'
    elif 39 >= confidence_value >= 20:
        return 'Unlikely/Probably Not'
    elif 59 >= confidence_value >= 40:
        return 'Even Chance'
    elif 79 >= confidence_value >= 60:
        return 'Likely/Probable'
    elif 99 >= confidence_value >= 80:
        return 'Highly likely/Almost Certain'
    elif confidence_value == 100:
        return 'Certain'
    else:
        raise ValueError("Range of values out of bounds: %s" % confidence_value)