mutation AddCustomerToCustomerGroups($input: AddCustomerToCustomerGroupsInput!) {
  addCustomerToCustomerGroups(input: $input) {
    customerGroupMemberships {
      customerId
      customerGroup {
        id
        name
        key
        color
        externalId
        createdAt {
          __typename
        }
      }
      createdAt {
        unixTimestamp
        iso8601
      }
      createdBy {
        __typename
        ... on UserActor {
          __typename
        }
      }
      updatedAt {
        unixTimestamp
        iso8601
      }
      updatedBy {
        __typename
        ... on UserActor {
          __typename
        }
      }
    }
    error {
      message
      type
      code
      fields {
        field
        message
        type
      }
    }
  }
}

{
  "input": {
    "customerId": "id",
    "customerGroupIdentifiers": [
      {}
    ]
  }
}

{
  "data": {
    "addCustomerToCustomerGroups": {
      "customerGroupMemberships": [
        {
          "customerId": "id",
          "customerGroup": {
            "id": "id",
            "name": "string",
            "key": "string",
            "color": "string",
            "externalId": "string",
            "createdAt": {
              "__typename": "DateTime"
            }
          },
          "createdAt": {
            "unixTimestamp": "string",
            "iso8601": "string"
          },
          "createdBy": {
            "__typename": "UserActor"
          },
          "updatedAt": {
            "unixTimestamp": "string",
            "iso8601": "string"
          },
          "updatedBy": {
            "__typename": "UserActor"
          }
        }
      ],
      "error": {
        "message": "string",
        "type": "VALIDATION",
        "code": "string",
        "fields": [
          {
            "field": "string",
            "message": "string",
            "type": "VALIDATION"
          }
        ]
      }
    }
  }
}