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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ed25519_private_key_to_string(key):
 """Convert an ed25519 private key to a base64-encoded string. Args: key (Ed25519PrivateKey):
 the key to write to the file. Returns: str: the key representation as a str """

    return base64.b64encode(key.private_bytes(
        encoding=serialization.Encoding.Raw,
        format=serialization.PrivateFormat.Raw,
        encryption_algorithm=serialization.NoEncryption()
    ), None).decode('utf-8')