package Ġcom . yes fer al . hor ns app . data . ab straction . storage Ċ Ċ interface ĠOn Board ing DataSource Ġ{ ĊĠĠĠ Ġfun Ġon Board ing Is Visible () Ġ: ĠBoolean ĊĠĠĠ Ġfun Ġhide On Board ing () Ċ } Ċ