input: Write a python function to check if two strings are rotations of each other.
  assert check_rotation("Hello World", "World Hello") == True
  assert check_rotation("abc", "cab") == True
  assert check_rotation("abc", "bca") == True
  assert check_rotation("abc", "acb") == False
  assert check_rotation("abcd", "abcd") == True
output: def check_rotation(s1, s2):
      if len(s1) != len(s2):
          return False
      return s2 in (s1 + s1)