diff --git a/lib/comma_splice/line_corrector.rb b/lib/comma_splice/line_corrector.rb
index 13e8540..03116e4 100644
--- a/lib/comma_splice/line_corrector.rb
+++ b/lib/comma_splice/line_corrector.rb
@@ -13,8 +13,8 @@ def initialize(header_line, value_line, left_bounds = 0, right_bounds = -1)
       @left_bounds = left_bounds
       @right_bounds = right_bounds
 
-      raise 'right bounds must be less than -1' unless right_bounds < 0
-      raise 'left bounds must be greater than zero' unless left_bounds >= 0
+      raise 'right bounds must be negative' unless right_bounds.negative?
+      raise 'left bounds must be not be negative' if left_bounds.negative?
     end
 
     def needs_correcting?
@@ -35,17 +35,8 @@ def corrected
       # the only values that could contain an extra comma are "artist,title,albumtitle,label"
       # therefore our left_bounds = 4, right_bounds = -5
 
-      values_before = if left_bounds > 0
-                        values[0..(left_bounds - 1)]
-                      else
-                        []
-                      end
-
-      values_after =  if right_bounds < -1
-                        values[(right_bounds + 1)..-1]
-                      else
-                        []
-                      end
+      values_before = values[0...left_bounds]
+      values_after = values.slice(right_bounds + 1, -(right_bounds + 1))
       [values_before, corrector.correction, values_after].flatten.join(',')
     end