I have the following Swagger definitions:

**NumberString.yaml**

type: string
pattern: ^d*.?d+$

**Bank.yaml**

type: object
properties:
  bank_account_number:
    allOf:
      - $ref: '../../Helpers/NumberString.yaml'
      - description: 'Bank Account Number'
        example: '337612234'
        maxLength: 9

NumberString represents a string that can only be a number; that’s why I have the digit pattern. Then, I have defined a Bank schema.

Have I defined bank_account_number correctly?

I am trying to ‘extend’ the NumberString schema, adding a maxLength, description and example.