Sets the customer_id of this ChargeRequest.
        The ID of the customer to associate this transaction with. This field is required if you provide a value for `customer_card_id`, and optional otherwise.

        :param customer_id: The customer_id of this ChargeRequest.
        :type: str

def customer_id(self, customer_id):
        """
        Sets the customer_id of this ChargeRequest.
        The ID of the customer to associate this transaction with. This field is required if you provide a value for `customer_card_id`, and optional otherwise.

        :param customer_id: The customer_id of this ChargeRequest.
        :type: str
        """

        if customer_id is None:
            raise ValueError("Invalid value for `customer_id`, must not be `None`")
        if len(customer_id) > 50:
            raise ValueError("Invalid value for `customer_id`, length must be less than `50`")

        self._customer_id = customer_id