install issue in iOS

[Odyflame]

pod 'RIBs', '~> 0.9'

when insert this code in podFile and run pod install, there is some issue that

CocoaPods could not find compatible versions for pod "RxSwift":
In snapshot (Podfile.lock):
    RxSwift (= 5.1.1, ~> 5, ~> 5.0)

  In Podfile:
    Moya/RxSwift was resolved to 14.0.0, which depends on
      RxSwift (~> 5.0)

    RIBs was resolved to 0.9.1, which depends on
      RxSwift (~> 4.0)

    RxCocoa was resolved to 5.1.1, which depends on
      RxSwift (~> 5)

    RxSwift

i think this error comes when RxSwift is already in podFile..