input: Write a function to determine if the first string contains the second string. If the first string contains the second, return True; otherwise, return False.
  
  assert check_contains("catering", "cat")==True
  assert check_contains("programming", "gram")==True
  assert check_contains("python", "foobar")==False
  assert check_contains("hello world", "world")==True
  assert check_contains("asteroid", "cat")==False
output: def check_contains(s1, s2):
      return s2 in s1