diff --git a/spleeter/commands/evaluate.py b/spleeter/commands/evaluate.py
index dc990ad..c2fe789 100644
--- a/spleeter/commands/evaluate.py
+++ b/spleeter/commands/evaluate.py
@@ -13,6 +13,7 @@
         --mus_dir /path/to/musdb dataset
 """
 
+import sys
 import json
 
 from argparse import Namespace
@@ -21,8 +22,6 @@ from glob import glob
 from os.path import join, exists
 
 # pylint: disable=import-error
-import musdb
-import museval
 import numpy as np
 import pandas as pd
 # pylint: enable=import-error
@@ -30,6 +29,15 @@ import pandas as pd
 from .separate import entrypoint as separate_entrypoint
 from ..utils.logging import get_logger
 
+try:
+    import musdb
+    import museval
+except ImportError:
+    logger = get_logger()
+    logger.error('Extra dependencies musdb and museval not found')
+    logger.error('Please install musdb and museval first, abort')
+    sys.exit(1)
+
 __email__ = 'research@deezer.com'
 __author__ = 'Deezer Research'
 __license__ = 'MIT License'
diff --git a/spleeter/model/functions/unet.py b/spleeter/model/functions/unet.py
index 245a5e5..245a247 100644
--- a/spleeter/model/functions/unet.py
+++ b/spleeter/model/functions/unet.py
@@ -3,10 +3,9 @@
 
 """
 This module contains building functions for U-net source separation source
-separation models.
-Each instrument is modeled by a single U-net convolutional/deconvolutional
-network that take a mix spectrogram as input and the estimated sound spectrogram
-as output.
+separation models. Each instrument is modeled by a single U-netconvolutional
+/ deconvolutional network that take a mix spectrogram as input and the
+estimated sound spectrogram as output.
 """
 
 from functools import partial