Y-axis Labels on Apex charts not getting properly displayed

I am trying to display the y-axis labels using the formatter function since i require the defects for the day to be displayed in the y-axis following is the screenshot of the view how i have obtained it. from the pic you can see the labels for y =0 not being displayed even though there is a poin on the graph.

def transform(self, value, quality, timestamp):

    defects = []
    lengths = []
    for row in value:
        defects.append(row['RESULT'])

    # get unique defects only
    defects = set(defects)
    # convert set back to list
    defects = list(defects)

    # create string to be returned
    listStr = "["
    for defect in defects:
        lengths.append(len(defect.strip()))
        # split strings so they get displayed on new lines
        if len(defect.strip()) >= 40:
            listStr += "'" + str(defect.strip().encode('ascii').split(' ', 2)) + "',"
        else:
            listStr += "'" + defect.strip().encode('ascii') + "',"
    listStr += "]"

    funcStr = 'function (val) {\
        var defects = ' + listStr + ';\
        return defects[val]\
        }'

    return funcStr```