Input 'stackConfig' defined multiple times in 'SwingStackComponent'

i’m trying to create a tinder cards app in ionic 2 following this tutorial https://devdactic.com/ionic-2-tinder-cards but got an error:

Error: Input 'stackConfig' defined multiple times in 'SwingStackComponent'
    at http://localhost:8100/build/main.js:31567:27
    at Array.forEach (native)
    at DirectiveResolver._merge (http://localhost:8100/build/main.js:31564:20)
    at DirectiveResolver._mergeWithPropertyMetadata (http://localhost:8100/build/main.js:31556:21)
    at DirectiveResolver.resolve (http://localhost:8100/build/main.js:31498:29)
    at CompileMetadataResolver.getNonNormalizedDirectiveMetadata (http://localhost:8100/build/main.js:32567:47)
    at CompileMetadataResolver._loadDirectiveMetadata (http://localhost:8100/build/main.js:32511:42)
    at http://localhost:8100/build/main.js:32777:87
    at http://localhost:8100/build/main.js:32692:99
    at Array.map (native)

Any solution?