input: Write a python function to calculate the sum of the series 1 + 1/2 + 1/3 + ... + 1/n.
  assert seriesSum(1) == 1.0
  assert seriesSum(2) == 1.5
  assert seriesSum(3) == 1.8333333333333333
  assert seriesSum(5) == 2.283333333333333
  assert seriesSum(10) == 2.928968253968254
output: def seriesSum(n):
      return sum(1/i for i in range(1, n+1))