how to calculate weekly average stock starting on monday? in python

main.py
def calculate_weekly_avg(stocks):
    if len(stocks) % 7 != 0:
        return "Invalid number of stock entries"

    weekly_avg = []
    start = 0

    while start < len(stocks):
        weekly_avg.append(sum(stocks[start:start+7]) / 7)
        start += 7

    return weekly_avg

# Example usage
stocks = [10, 12, 13, 15, 17, 19, 20, 22, 21, 20, 23, 25, 24, 26, 27, 29]
print(calculate_weekly_avg(stocks))
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