$4.(25$ points$)$ A leap year is a year that is an integer multiple of $4,$ except for years evenly divisible by $100,$ but not by $400.$ For example, the year $2020$ was a leap year, since $\backslash (2020=4\backslash$times $505\backslash ).$ However, the year $2100$ will not be a leap year, since it is evenly divisible by $100,$ but not by $400.$ Write a function in Python that determines whether a given year is a leap year or not. Hint: Use the $"\backslash \%"$ operator in Python. A number x is divisible by another number y if $\backslash (\backslash$mathrm$\{$x$\}\backslash \%\backslash$mathrm$\{$y$\}=0\backslash ).$ If x is not divisible by y $,$ then $\backslash (\backslash$mathrm$\{$x$\}\backslash \%\backslash$mathrm$\{$y$\}$

eq $0\backslash ).$