input: Write a python function to count how many 'boredom' sentences are present in a string. A 'boredom' sentence starts with the word 'I'. Sentences in the string are demarcated by '.', '?' or '!'.
  assert is_bored("Hello world") == 0
  assert is_bored("Is the sky blue?") == 0
  assert is_bored("I love It !") == 1
  assert is_bored("bIt") == 0
  assert is_bored("I feel good today. I will be productive. will kill It") == 2
  assert is_bored("You and I are going for a walk") == 0
output: def is_bored(s):
      sentences = s.split('. ') + s.split('? ') + s.split('! ')
      count = 0
      for sentence in sentences:
          if sentence.strip().startswith('I '):
              count += 1
      return count