def get_showable_lines(self) -> int:
    """
    Return the number of lines which are shown. Less than maximum if less lines are in the array.
    """
    if self.showable_line_numbers_in_editor + self.showStartLine < self.maxLines:
        return self.showable_line_numbers_in_editor + self.showStartLine
    else:
        return self.maxLines