usage?

How is this supposed to be used?

I tried adding the standard:
```python3
if __name__ == "__main__":
    import sys
    from PyQt5.QtWidgets import QApplication
    app = QApplication(sys.argv)
    main = Terminal(None)
    main.setGeometry(1, 1, 800, 600)
    main.show()
    sys.exit(app.exec_())
```
but it just displays a black window with no way to interact.
What am I missing?