'Add text to combo box: add a new item if text is not found in
combo box items.'

def add_text(self, text):

    index = self.findText(text)
    while (index != (-1)):
        self.removeItem(index)
        index = self.findText(text)
    self.insertItem(0, text)
    index = self.findText('')
    if (index != (-1)):
        self.removeItem(index)
        self.insertItem(0, '')
        if (text != ''):
            self.setCurrentIndex(1)
        else:
            self.setCurrentIndex(0)
    else:
        self.setCurrentIndex(0)
