package Ġio . lam art . gyro . mutable Ċ Ċ import Ġio . lam art . gyro . variables . Variable Type Ċ Ċ interface ĠMutable Type < T > Ġ: ĠVariable Type < T > Ġ{ ĊĊĠĠĠ Ġfun Ġfilter ( predicate : ĠT . () Ġ-> ĠBoolean ): ĠOptional Mutable < T > Ċ Ċ } Ċ Ċ inline Ġfun Ġ< re ified ĠR > ĠMutable Type <* >. filter Cast () Ġ= Ġfilter ( R :: class . java :: is Instance ). cast < R >() Ċ