def coerce(value)
        return SpreadSheet.new([value]) if value.is_a?(Numeric)
        return SpreadSheet.new(value)   if value.is_a?(Array)
      end
def coerce(value)
        return SpreadSheet.new([value]) if value.is_a?(Numeric)
        return SpreadSheet.new(value)   if value.is_a?(Array)
      end
Coerces a number or an array to a spread sheet