Graphql 如何使用；“随机”；突变图中的变量？

救命啊。Postman具有内置的随机变量（例如$randomInt、$randomNamePrefix）。我如何在突变中使用它们？我正在使用$randomNamePrefix-不幸的是，这不起作用

mutation SaveOrderOutInput {
saveOrderOut (input: {fio: {firstName: $randomNamePrefix, lastName: "Ivanovd", middleName: "Loshdya"}, address: {postIndex: "43434", city: "Kolyama", address: "Koko d.5 oe. 3"}, passport: {citizenship: "Ангола", passportId: "3265 748742", passportAuthority: "Ufms Ksd Jw pfd", passportIssueDate: "01/07/2000"}}){
ok
orderOut {
  id
  firstName
  middleName
  lastName
  postIndex
  city
  address
  citizenship
  passportId
  passportAuthority
  passportIssueDate
}
    clientMutationId
 }
}

封装在

{{$$randomNamePrefix}}

就这样吧

mutation SaveOrderOutInput {
saveOrderOut (input: {fio: {firstName: {{$randomNamePrefix}}, lastName: "Ivanovd", 
middleName: "Loshdya"}, address: {postIndex: "43434", city: "Kolyama", address: "Koko d.5 oe. 3"}, passport: {citizenship: "Ангола", passportId: "3265 748742", 
passportAuthority: "Ufms Ksd Jw pfd", passportIssueDate: "01/07/2000"}}){
ok
orderOut {
 id
 firstName
 middleName
 lastName
 postIndex
 city
 address
 citizenship
 passportId
 passportAuthority
 passportIssueDate
}
clientMutationId
}
}