diff --git a/lib/cdr.rb b/lib/cdr.rb
index b8077378605cdd995d06fff3ada51ceebfd14e77..de9d1f43cc58fd37a5368349181a7b2c092d0c2a 100644
--- a/lib/cdr.rb
+++ b/lib/cdr.rb
@@ -3,12 +3,31 @@
 require "value_semantics/monkey_patched"
 
 class CDR
+	module Disposition
+		def self.===(other)
+			["NO ANSWER", "ANSWERED", "BUSY", "FAILED"].include?(other)
+		end
+
+		def self.for(cause)
+			case cause
+			when "timeout", "rejected", "cancel"
+				"NO ANSWER"
+			when "hangup"
+				"ANSWERED"
+			when "busy"
+				"BUSY"
+			else
+				"FAILED"
+			end
+		end
+	end
+
 	value_semantics do
 		cdr_id String
 		customer_id String
 		start Time
 		billsec Integer
-		disposition Either("NO ANSWER", "ANSWERED", "BUSY", "FAILED")
+		disposition Disposition
 		tel(/\A\+\d+\Z/)
 		direction Either(:inbound, :outbound)
 	end
@@ -49,19 +68,4 @@ class CDR
 			VALUES ($1, $2, $3, $4, $5, $6, $7)
 		SQL
 	end
-
-	module Disposition
-		def self.for(cause)
-			case cause
-			when "timeout", "rejected", "cancel"
-				"NO ANSWER"
-			when "hangup"
-				"ANSWERED"
-			when "busy"
-				"BUSY"
-			else
-				"FAILED"
-			end
-		end
-	end
 end