In constructor

const In([
  1. IdentifierableCollection first = const IdentifierableCollection(CitrusSyntaxList([LowercaseAlphabetI(), LowercaseAlphabetN()]))
])

Implementation

const In([
    this.first = const IdentifierableCollection(
        CitrusSyntaxList([
            LowercaseAlphabetI(),
            LowercaseAlphabetN(),
        ])
    )
]);