数に応じて日を言葉で表す次のヘルパーがあります。
def day_in_words(number)
case number
when 0
"Sunday"
when 1
"Monday"
when 2
"Tuesday"
when 3
"Wednesday"
when 4
"Thursday"
when 5
"Friday"
when 6
"Saturday"
when 7
"Sunday"
when 8
"Monday"
when 9
"Tuesday"
when 10
"Wednesday"
when 11
"Thursday"
...
when 16
"Sunday"
when 17
"Monday"
when 18
"Tuesday"
when 19
"Wednesday"
when 20
"Thursday"
when 21
"Friday"
else
"Unknown Day"
end
end
そのヘルパーをリファクタリングする方法は?