input: Write a function to check if the given string contains the word "Hello". If it does, return True, otherwise return False.
  
  assert check_hello("Hello, world!")==True
  assert check_hello("Hi, there!")==False
  assert check_hello("HelloHello")==True
  assert check_hello("")==False
  assert check_hello("Say hello")==False
output: def check_hello(s):
      return "Hello" in s