input: Write a python function to calculate the highest sum of subsequences in a given array where no two elements are adjacent.
  assert calculate_max_sum_subseq([1, 2, 9, 4, 5, 0, 4, 11, 6]) == 26
  assert calculate_max_sum_subseq([1, 2, 9, 5, 6, 0, 5, 12, 7]) == 28
  assert calculate_max_sum_subseq([1, 3, 10, 5, 6, 0, 6, 14, 21]) == 44
output: def calculate_max_sum_subseq(arr):
      if not arr:
          return 0
      incl = 0
      excl = 0
      for num in arr:
          new_excl = max(incl, excl)
          incl = excl + num
          excl = new_excl
      return max(incl, excl)