diff --git a/src/rougail/user_data_commandline/__init__.py b/src/rougail/user_data_commandline/__init__.py
index 5e5ce9a..7be358b 100644
--- a/src/rougail/user_data_commandline/__init__.py
+++ b/src/rougail/user_data_commandline/__init__.py
@@ -18,7 +18,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from argparse import ArgumentError
 from tiramisu_cmdline_parser import TiramisuCmdlineParser
-from rougail.error import ExtentionError
+from rougail.error import ExtensionError
 
 from .i18n import _
 from .__version__ import __version__
@@ -48,7 +48,7 @@ class RougailUserDataCommandline:
                 rougailconfig["step.user_data"] = user_data
         user_data = rougailconfig["step.user_data"]
         if "commandline" not in user_data:
-            raise ExtentionError(_('"commandline" is not set in step.user_data'))
+            raise ExtensionError(_('"commandline" is not set in step.user_data'))
         self.rougailconfig = rougailconfig
         self.arguments = arguments
         self.errors = []