diff --git a/testgres/exceptions.py b/testgres/exceptions.py
index 20c1a8cf..fcbb6c7c 100644
--- a/testgres/exceptions.py
+++ b/testgres/exceptions.py
@@ -29,7 +29,7 @@ def __str__(self):
             msg.append(self.message)
 
         if self.command:
-            command_s = ' '.join(self.command) if isinstance(self.command, list) else self.command,
+            command_s = ' '.join(self.command) if isinstance(self.command, list) else self.command
             msg.append(u'Command: {}'.format(command_s))
 
         if self.exit_code: