def gCallbackCov(dataset, colors):
    """Callback to set initial value of green slider from dict.

    Positional arguments:
    dataset -- Currently selected dataset.
    colors -- Dictionary containing the color values.
    """
    colorsDict = colors
    try:
        colorVal = colorsDict[dataset][4:-1].split(',')[1]
        return int(colorVal)
    except KeyError:
        return 0