@idempotency_key.setter<EOL><INDENT>def idempotency_key(self, idempotency_key):<DEDENT>
if idempotency_key is None:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>if len(idempotency_key) > <NUM_LIT>:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>if len(idempotency_key) < <NUM_LIT:1>:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>self._idempotency_key = idempotency_key<EOL>
Sets the idempotency_key of this CreateCheckoutRequest.
A unique string that identifies this checkout among others you've created. It can be any valid string but must be unique for every order sent to Square Checkout for a given location ID.  The idempotency key is used to avoid processing the same order more than once. If you're unsure whether a particular checkout was created successfully, you can reattempt it with the same idempotency key and all the same other parameters without worrying about creating duplicates.  We recommend using a random number/string generator native to the language you are working in to generate strings for your idempotency keys.  See [Idempotency](/basics/api101/idempotency) for more information.

:param idempotency_key: The idempotency_key of this CreateCheckoutRequest.
:type: str