diff --git a/lib/uplot/command.rb b/lib/uplot/command.rb
index 2451239..f64a9bd 100644
--- a/lib/uplot/command.rb
+++ b/lib/uplot/command.rb
@@ -1,6 +1,6 @@
 require 'optparse'
-require 'csv'
 require 'unicode_plot'
+require_relative 'preprocessing'
 
 module Uplot
   Data = Struct.new(:headers, :series)
diff --git a/lib/uplot/preprocessing.rb b/lib/uplot/preprocessing.rb
index 6bdf76f..4a4a2c9 100644
--- a/lib/uplot/preprocessing.rb
+++ b/lib/uplot/preprocessing.rb
@@ -1,3 +1,5 @@
+require 'csv'
+
 module Uplot
   module Preprocessing
     module_function