testcases:
  - name: "testcase 1"
    inputs:
    - 1 : [1, 2, 3]
    - 2 : [1, 2, 3]
    output: 
    - 1 : [1, 1, 2, 2, 3, 3]
  - name: "testcase 2"
    inputs:
    - 1: [25, 33, 99]
    - 2: [1]
    output:
    - 1 : [1, 25, 33, 99]
  - name: "testcase 3"
    inputs:
    - 1: []
    - 2: [7]
    output:
    - 1 : [7]
  - name: "testcase 4"
    inputs:
    - 1: [-77, 0, 5]
    - 2: [1, 2, 7]
    output:
    - 1 : [-77, 0, 1, 2, 5, 7]
  - name: "testcase 5"
    inputs:
    - 1: []
    - 2: []
    output:
    - 1 : []