keys( %$_ )         
keys( %$_ ) [0]     Nonsense
keys( %$ ); [0]     `;` = End of statement
keys( %$ )  # [0]   `#` = Comment
keys( %$ ) ^ [0]    `^` = Binary op
keys( %$ ) & [0]    `&` = Binary op
keys( %$ ) = [0]    `=` = Binary op
keys( %$ ) | [0]    `|` = Binary op
keys( %$ ), [0]     `,` = Binary op
keys( %$ ) < [0]    `<` = Binary op
keys( %$ ) > [0]    `>` = Binary op