prize13-7, Exercise 3: Adding Alekhine

Model answer (check the details):

    reigns = [
        ("Steinitz", 1886, 1894),
        ("Lasker", 1894, 1921),
        ("Capablanca", 1921, 1927),
        ("Alekhine", 1927, 1935),
    ]

The new output line is:

    Alekhine     8 years

The longest reign is still Lasker's, with 27 years.

What a calendar-year count leaves out: the matches took place at particular dates within each year, so a reign counted from 1927 to 1935 may be a few months longer or shorter than eight years. Alekhine also held the title a second time (1937 to 1946), so one entry gives only part of his total, and the gap of 1946 to 1948 when the title was vacant does not fit a simple list of years at all.

Care: the years are those given in standard lists; check exact match dates.