input: Write a python function to compare two strings in a case-insensitive manner.
  assert case_insensitive_compare("Hello", "hello") == True
  assert case_insensitive_compare("World", "world") == True
  assert case_insensitive_compare("Python", "python") == True
  assert case_insensitive_compare("OpenAI", "OpenAI") == True
  assert case_insensitive_compare("Test", "Fail") == False
output: def case_insensitive_compare(str1, str2):
      return str1.lower() == str2.lower()