<s>[INST] Here is an example of a class representing rectangle.
```python
class Rectangle:
    def __init__(self, width, height):
        self.width = width
        self.height = height
        self.area = width * height

    def scale(self, factor):
        self.width *= factor
        self.height *= factor
        self.area = self.width * self.height

    def __str__(self):
        return f"Rectangle({self.width}, {self.height})"


# Example usage:
rect = Rectangle(10, 20)
print(rect)  # Prints: Rectangle(10, 20)

rect.scale(2)
print(rect)  # Prints: Rectangle(20, 40)
```
The given example class represents a rectangle, but it violates some principal of class design. What is the major issue with this code?[/INST]