input: Write a function to encrypt a string using Caesar Cipher with a given key.
  assert caesarCipherEncryptor("abc", 2) == "cde"
  assert caesarCipherEncryptor("xyz", 2) == "zab"
  assert caesarCipherEncryptor("hello", 5) == "mjqqt"
output: def caesarCipherEncryptor(string, key):
      encrypted_string = []
      for char in string:
          new_char_code = (ord(char) - ord('a') + key) % 26 + ord('a')
          encrypted_string.append(chr(new_char_code))
      return ''.join(encrypted_string)