item = BoundingBox()

pen = QPen()
pen.setStyle(Qt.DashLine)
pen.setWidth(3)
pen.setColor(QColor(0, 0, 0))

item.setPen(pen)

from PyQt5.QtWidgets import QWidget, QGraphicsView, QVBoxLayout, QApplication, QGraphicsScene

from pyqt_bounding_box.boundingBox import BoundingBox


class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.__initUi()

    def __initUi(self):
        view = QGraphicsView()
        self.__scene = QGraphicsScene()
        self.__scene.setSceneRect(0, 0, 400, 400)

        item = BoundingBox()
        # item.setLineWidth(8) If you want to change the edge line width, add the code.
        # item.setColor(QColor(255, 255, 255)) If you want to change the color of the line to white, add the code.
        # item.setStyle(Qt.SolidLine) If you want to change the style of line from dashed to solid line, add the code.
        self.__scene.addItem(item)
        view.setScene(self.__scene)

        lay = QVBoxLayout()
        lay.addWidget(view)

        self.setLayout(lay)


if __name__ == "__main__":
    import sys

    app = QApplication(sys.argv)
    example = Example()
    example.show()
    app.exec_()