Protected ReadonlyargsOptionalmethodArgs: {OptionalmethodArgs: {When using this endpoint, if omitted, the Customer stores field is set to the Store specified in the path parameter.
If a Cart with a `store` field specified, the `store` field must reference the same [Store](ctp:api:type:Store) specified in the `{storeKey}` path parameter.
Allows converting an anonymous Cart to the active Cart of a Customer with [cart merge](/../api/customers-overview#cart-merge-during-sign-in-and-sign-up).
If the Customer has multiple active Carts, the anonymous Cart is merged into the most recently modified active Cart.
Creating a Customer produces the [CustomerCreated](ctp:api:type:CustomerCreatedMessage) Message. Simultaneously creating two Customers with the same email address can return a [LockedField](ctp:api:type:LockedFieldError) error.
Checks if one or more Customers exist for the provided query predicate. Returns a
200status if any Customers match the query predicate, or a404status otherwise.