**Instructions: **

You will be creating several functions (all in the same file).
Be sure to include, after each function, the appropriate test cases that you've
devised. There must be at least 2 test cases for each function, in the
following format:

print("fred(18) should be 34, and is: ", fred(18))
After using the test lines, you may comment them out.

- Create the function
*sum_squares(low,high)*which will be given two integers, with the requirement that*low <= high*. The function will add up all of the squares of the numbers between (and including) low and high and return tthat value. Be sure to include test cases to validate your function.

- Create the function
*sum_powers(low,high,power)*which will be given two integers and a power (which is a number that is not necessarily an integer or even a positive number), with the requirement that*low <= high*. The function will add up all of the powers of the numbers between (and including) low and high and return that value. For instance, of power is 2, then it's the sum of squares. If it's 3 then the sum of cubes, etc.

- Create the function
*SUM_POWERS(a,b,power)*which will be given two integers and a power, like the one above, except that we're not guaranteeing that*a <= b*. You may use a previously battle-tested function as a helper function.

- Create the function
*fizzbuzz**(n),*which will be given a number*n >= 1.*It will print out all the numbers from 1 to n, except: if a number is divisible by 3, it will print out "fizz" instead, if it's divisble by 5 then "buzz" instead and if divisible by both, then "fizzbuzz" instead. All other numbers are printed out in numerical form. The function will not return anything (no*return*statement).

- Create the function
*num_digits(n)*which will be given a positive integer n, and will return the number of digits in the decimal representation of n. For instance, num_digits(105) returns 3, num_digits(8) returns 1. Remember that the % operator gives you the remainder (e.g. 17 % 4 gives you 1) and that the // operator is quotient (e.g. 21 // 4 gives you 5) -- you'll need these.

**Challenge problem (optional):**

Create the function *bin_to_dec(n),* which will be given a number in
binary (only 1's and 0's), and will return the decimal equivalent of it.

Examples:

*bin_to_dec(10)* -> 2

*bin_to_dec(101)* -> 5