Calculate Image Brightness

Task: Image Brightness Calculator

In this task, you will implement a function calculate_brightness(img) that calculates the average brightness of a grayscale image. The image is represented as a 2D matrix, where each element represents a pixel value between 0 (black) and 255 (white).

Your Task:

Implement the function calculate_brightness(img) to:

1. Return the average brightness of the image rounded to two decimal places.
2. Handle edge cases:
   • If the image matrix is empty.
   • If the rows in the matrix have inconsistent lengths.
   • If any pixel values are outside the valid range (0-255).

For any of these edge cases, the function should return -1.

def calculate_brightness(img):
	# Write your code here
	pass