package Ġview . utils . map Based . keys . deleg ates Ċ Ċ import Ġview . core . loaders . builders . View Keys Ċ import Ġview . utils . map Based . keys . deleg ates . nullable . Nullable RW Key Ċ import Ġview . utils . map Based . keys . deleg ates . required . Required RW Key Ċ Ċ class ĠKeys Stub : ĠView Keys () Ġ{ ĊĊĠĠĠ Ġvar Ġrequired Key Ġby ĠRequired RW Key Ġ{ Ġit . to Boolean () Ġ} ĊĠĠĠ Ġvar Ġnullable Key Ġby ĠNullable RW Key Ġ{ Ġit . to Boolean () Ġ} Ċ }