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