input: Write a function to return True if the given string contains the word "Hello", otherwise return False. The function should take a single string parameter.
  assert check_hello("Hello World")==True
  assert check_hello("Goodbye World")==False
  assert check_hello("Hello")==True
  assert check_hello("hello")==False
  assert check_hello("")==False
output: def check_hello(s):
      return "Hello" in s