input: Write a function that calculates the sum of squares of all the numbers from 1 to N. The function should take a single integer argument N and return the sum of squares.
  
  def sum_of_squares(n):
      result = 0
      for i in range(1, n+1):
          result += i**2
      return result
  
  assert sum_of_squares(1)==1
  assert sum_of_squares(2)==5
  assert sum_of_squares(3)==14
  assert sum_of_squares(4)==30
output: def sum_of_squares(n):
      result = 0
      for i in range(1, n+1):
          result += i**2
      return result