Failing to add newly created cocoa pod to private pod spec

I'm following to following tutorial - How to Create a CocoaPod in Swift.

I'm stuck at the last step - Using Your New CocoaPod

You first need to add your Podspec to a private specs repo; this lets CocoaPods find the pod when you try to install it. Fortunately, you’ve already created a Git repo for this, so this final step is relatively straightforward.

Enter the following in Terminal, making sure you’re still in the RWPickFlavor directory:

pod repo add RWPodSpecs [Your RWPodSpecs Git URL]
pod repo push RWPodSpecs RWPickFlavor.podspec

I get this fatal error:

fatal: destination path 'RWPodSpecs' already exists and is not an empty directory.

I've removed the repo and created it again according to the "Setting Up Your GitHub Repo" tutorial step. But I get this error still.

Any ideas?

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