mutation ImportCustomers($input: ImportCustomersInput!) {
  importCustomers(input: $input) {
    result {
      added
      updated
      skipped
    }
    error {
      message
      type
      code
      fields {
        field
        message
        type
      }
    }
  }
}

{
  "input": {
    "customers": [
      {
        "externalId": "string",
        "fullName": "string",
        "tenants": [
          {
            "externalId": "string",
            "name": "string"
          }
        ]
      }
    ]
  }
}

{
  "data": {
    "importCustomers": {
      "result": {
        "added": 1,
        "updated": 1,
        "skipped": 1
      },
      "error": {
        "message": "string",
        "type": "VALIDATION",
        "code": "string",
        "fields": [
          {
            "field": "string",
            "message": "string",
            "type": "VALIDATION"
          }
        ]
      }
    }
  }
}