How can I force virtual keyboard to appear when a physical keyboard is attached using swift on Xcode 8?

I am using a barcode scanner and a NFC card reader attached to my iOS device, they are both detected as keyboards by iOS. At some point in my application, I need the virtual to appear when a text field is selected. How can I force the virtual keyboard to appear in this situation? I am using Xcode 8 and swift.

Thanks

How can I force virtual keyboard to appear when a physical keyboard is attached using swift on Xcode 8?
 
 
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