input: Write a function to determine if a given string contains the word "Hello". If it does, return True, otherwise return False. If the given string is empty, return False.
  assert check_hello("Hello, world!")==True
  assert check_hello("Hi there!")==False
  assert check_hello("This is a test with Hello")==True
  assert check_hello("No greetings here")==False
  assert check_hello("")==False
output: def check_hello(s):
      if not s:
          return False
      return "Hello" in s